I've been running a Shindaiwa C-35 for the last 20+ years with very little trouble.

I don't know it it is the best, but it works for me.

Good luck finding a definitive answer to your question....I don't know that there is one "best" weed trimmer brand. It's kind of like Ford vs Chevy vs Dodge vs whatever. Several companies make high quality, commercial grade trimmers including Stihl, Echo, Shindaiwa, Redmax & Honda. You might want to go to lawnsite.com & check some posts there about weed trimmers. Those guys are pros who use the things everyday. You'll get some blind brand loyalty from a few people on the site but if something stinks or doesn't hold up well you'll hear about that too. Your budget, the warranty offered, dealer location & support are all factors to consider in your choice. Good luck.

low end units tend to shake themselves to death every couple of years, whether replacing a low end unit every few years, or maintaining a high end unit is worthwhile. I'm on my 2nd Toro after the first one fell apart after a few years.

not an answer to your question, just wanted to comment.

One that runs when you pull the cord! Hee, HEE!

I agree with "colonel428" totally. Go to lawnsite to read, read a lot. I am very active there, there are a few people that tell you to buy Stihl 4Mix even though I did poll and also a lot of people complain about their reliability. You stay with Echo, Redmax, Shindaiwa 2 cycles, you really cannot go wrong. Go to the store, pick one up and see how you like it.
Husqvarna are light and not bad at all.

I would say, look for sales, note the model down, go read the lawnsite. 2 CYCLES ONLY unless you are willing to get Honda type which are heavier than all 2 cycles.

I use Honda trimmer and Honda engine Mantis and I love it. I can't tell you to get Honda because it is heavy if you use extended period of time. But it you see one, take a look.

Bottom line I agree with rcmoser, but I will have to put in my two cents and say that after running Stihl, Echo, Husqvarna and Shindaiwa I am pretty much settled on Maruyama. By the way the Husqvarna I owned (early 90s) had an engine made by Maruyama although I don't think this is the case these days. I have not yet tried a four cycle machine as I have been unable to shake my distrust of this newfangled technology. I will have to buy a truck soon because my horse is getting pretty old. Cheers!

COSTCO's model for the year has a 4 stroke 25cc Honda engine. My preference is for a 4 stroke engine vs 2-stroke. I just hate the chore of mixing gas and oil.

If you want a 4 cycle with separate oil, get the Honda HHT25S or The Husqvarna 324L trimmer. These are commercial quality trimmer with Honda engine.