The Lily Garden's bulbs could be bigger, but you can not go wrong with JS either. You will get very healthy bulbs from both sellers. The LG has better selection and lots of their own hybrids. IMHO, it is really about varieties you want to buy. Both sellers are fantastic.
Check out Brent and Becky's stock as well. Their prices are a little higher than JS, but lower than the LG's. They are in the same climate zone, so their bulbs always grow very well here in Maryland.

It's a little like saying what is the difference between a Mercedes and a Honda. Not much if you just want to reliably get from point A to point B.

The Lily Garden grow their lilies in their own fields. John Scheepers is a dutch importer. If you are looking for commonly available varieties, you want a reasonably large number of lilies and you don't mind waiting for the bulbs to mature a little than John Scheepers is a very good choice.

If you are looking for unique lilies, and/or bulbs that are large, very healthy, and freshly dug then you can't do better than The Lily Garden.

When I've wanted a bunch of a variety to fill an area I've bought from John Scheepers and have been happy with them. But if I wanted to "collect" one or two of a special lily or lilies for a prominent location in my garden where I wanted a few special lilies that would look really good right away then The Lily Garden will work well.

-Helen

Thanks for the input. I was thinking of getting the "season of bloom" from the Lily Garden (which is 10 bulbs that provide a long season of flowers) and the Orienpet and maybe asiatic collections from John Scheepers. It sounds like the Scheepers will be smaller and grow more over the years? Any ideas are appreciated.

The JS bulbs will be big enough to bloom the first year after planting with 2-4 blooms per bulb. If you are not picky about color, it sounds like a good idea for starting your lily collection.