I bought a kit from Avery and have been very happy with the quality and service. I have also bought a few extra items (i.e. tank dimple dies) from Cleaveland and they were great, too.
It is hard to compare kits strictly on price. One may have an extra yoke or something else that may or may not prove necessary. So, you really have to look at the kit contents as well. Of course, if you ask 10 builders what is "necessary" you will get 14 different answers. The good news is that if you need something, both Avery and Cleaveland (and maybe some others as well) ship it out pretty quickly.
It is also difficult to tell when to buy name brand and when not to. I agree whole heartedly with the post that said you won't regret buying good tools. I have been suckered into buying some power tools from Harbor Freight and have mostly been dissapointed. I really like the Sioux drill that came with the Avery kit. I did not upgrade the 2X rivet gun to Sioux. However, the one that came with the kit has performed very well.
On service... I dropped my drill and the countersink cutter and cage were in it at the time. The drill is fine. However, the countersink cage is now more appropriate for countersinking around a corner.

I mentioned this to Bob Avery at SNF last year and he told me to send it back to him and he would straighten it out. I had purchased it from him 3-4 years ago and it certainly wasn't anyone's fault but mine that it was damaged. I didn't take him up on the offer, but it was very nice of him to offer. Guess where I bought my replacement countersink cage...