I think it depends on the variety you plant. I like a flat podded bean myself so for pole beans I use Kwintus from Park Seeds and bush beans I use Tennessee Green Pod from R.H. Shumways.

As garden fool said...the variety determines whether or not it has strings. I have grown both but actually prefer the climbers because they just keep on producing. I have found with bush beans that by the time they finish the second flush of beans, they plants are raggedy and straggly and ready to be pulled...my climbers produce all summer until frost...I just love Rattlesnake.

Some pole beans have strings which need to be removed, others are stringless. I don't know which kind has the most varieties but I feel safe in saying that the varieties most gardeners these days are growing are stringless varieties. There are many to choose from.

Jim

I've grown Fortex pole beans. Fortex is stringless and delicious and a great producer over a couple weeks. I am growing these beans again this year.

Jon

And Fortex is a pole bean.

The growth habit doesn't determine whether the pods have strings or not.

George

Bush bean Contender has beans in 45 days, so I use it and other bush beans to give me a crop while I'm waiting for the pole beans, 60-80 days, but for eating quality I'll take pole beans any day, usually larger, more succulent, and better flavor, especially varieties I have grown like Jeminez and Uncle Steve's. I haven't tried Rattlesnake. Kwintus can get fibrous as it gets older, Fortex was great in San Diego but didn't grow well for me here the one time I tried it. I'm trialing some other pole beans this year... as well as some Runner beans, the other species pole beans with red flowers.

My own preferences are much the same as Hemnancy's; I prefer pole beans for their size, flavor, and yield... and for the enormous variation available in heirloom varieties. They require more space, but that is not an issue for me. Bush beans, however, have their advantages too... so sometimes (preferences aside) it's a question of which type is most suitable for the location & the intended purpose. It's also worth noting that beans should be considered for more than just snaps.

Bush beans
Advantages:
- Easy to plant, require no support.
- They mature more quickly. This makes them better suited for short-season areas, for late planting, and when they will be grown early or late as part of a succession planting.
- Generally bear all-at-once, so good if grown for canning in large batches, especially with limited space.
- Low profile, so better suited for high-wind areas.
- Most popular dry beans are bush varieties.
- More wax bean varieties available commercially as bush than as pole.
Disadvantages:
- Less suitable for kitchen gardens, where a prolonged harvest is preferable. Succession planting every few weeks can overcome this, if space is available to do so.
- More vulnerable to damage by slugs and rodents.
- Lower yield.*
- Generally smaller pod size.
- Fewer cultivars available for use as shellies.
- Harvest can be uncomfortable, due to constant bending.

Pole beans
Advantages:
- Higher yield*, sometimes enormous.
- Generally larger pods as snaps, so less cutting involved for canning.
- More varieties available for shellies, including most of the larger-seeded.
- Prolonged harvest, good for fresh eating over a long period. Some varieties, though, will have large flushes in a relatively short period of time.
- Pods are higher, making them easy to see & pick, with minimal bending.
- Less damage from rodents, snails, & crawling insects.
Disadvantages:
- Require erecting a pole/trellis. Not too tough for a 20-foot row, but 500 feet of trellis can be a chore.
- Take longer to bear, making them less suitable for short season areas. (There are, however, fast-maturing varieties like "Goldmarie" and "Early Riser").
- Except for very long-season areas, they occupy the ground for the entire season, so not suitable for succession planting.
- Not good for high-wind areas, where poles & vines may be snapped.
- While the over-all yield is very high, the yield-per-plant for a given period may be relatively low, so smaller daily pickings. This is only an issue where space is limited.
- Few varieties commercially available for dry beans (but many heirlooms).

I have also observed that many bean diseases are either caused or aggravated by soil being splashed on the leaves; bush beans seem to be more vulnerable to this.

I used the (*) for yield, because with different planting strategies, either bush or pole can be high-yielding:
- Pole varieties have a higher yield per plant, and often the highest yield per row foot... but much of this advantage is lost with multiple rows, because of the greater row spacing required due to shading. They are at their best if planted in a single row, at the North side of the garden. My largest yield per row by far was from a row of "Pole 191" snap beans.
- Bush varieties, while yielding less per plant, can be spaced more closely... and since shade is not an issue, the rows can be closer together as well. Succession planting can also help overcome the yield gap, since it allows bush beans to time-share a given space with another crop.

I think that the best bean strategy is a single row of pole beans on the North side - with a row or two of bush beans directly adjacent on the South side - so as to form one wide row. This gives the best of both worlds, in a relatively small space. Those pole beans, by the way, can include limas or yardlong beans.

As for strings, I think there is little difference; there are both pole beans & bush beans, with- and without strings. However, since most breeding going on now is for bush beans, there will eventually be more stringless varieties available as bush.

I don't necessarily see "stringlessness" as an advantage, since many varieties that develop strings are stringless when picked young, and have outstanding flavor. "Kentucky Wonder" is a great example of this. Most of the new bush varieties, while stringless, are of the petite style now popular in Europe... takes a lot of picking to get a basket full. No thank you. Give me the 11" pods of "Fortex", or the long pods of "Goldmarie" or "Garafal Oro", any day.

zeedman, you should write a book about beans! maybe you have already?

I wanted to add a recent observation on comparing the same variety as bush and pole. I know the original question was about beans and not peas, but I have been harvesting a lot of peas recently, and well, they are legumes too (and so delicious!). I got both bush and pole of both snow peas and sugar snaps, the two types with the edible pods. The bush ones are not really so bush, they seem to still need a bit of support and are almost as tall as me, well most are at least 4 feet. This seems to be true of both the snow and sugar pods. So here is the observation. For the sugar snaps there does not seem to be much difference between the sugar snaps harvested from the pole or bush variety. Perhaps the pole ones are slightly larger. However, big difference with the snow pea pods. I get much bigger pods from the pole snow peas and they can get a lot bigger before getting tough and getting strings. The bush-like type need to be harvested a lot smaller (and sooner) for good eating.

So next year (I mean latter this year) I will plant both snow peas and sugar snaps as pole peas, but I might only do the sugar snaps as bush or bush-like peas to use as nitrogen fixers/cover crops. Just my $0.02.