Rather than buying a kit, I picked and chose what I wanted from Avery, BrownTool and The Yard. By doing this I was able to get pretty much everything in the 'standard kits', PLUS a used pneumatic squeezer ('Used' as in "..was probably used to build B52's!..")
Here is my take on the vendors I have experience with:
The Yard (
www.yardstore.com) -- Great for used tools at good prices (bought my squeezer from them)
BrownTool - New tools (especially during sales!) and most 'off the shelf' bits and pieces (drill bits, abrasives, dies, hand tools, etc). Sometimes they will also have used tools on sale (such as a pneumatic 90 degree drill, probably just as old as my squeezer). I bought most of my clecos from them because they have free shipping on orders over $95
Avery -- Somewhat higher-priced, but any 'custom' tool they make is well worth the money. Their vice-grip based tools (seaming pliers, dimplers) are a must-have, and their back-riveting plate is a work of art. For those of us in Texas, they also have the advantage that UPS ground will usually deliver my order within 1 day.
As far as support, I've had product 'issues' with stuff bought at all three places, and it has alway been a very positive experience.
By the way, at some point during your build, you will feel the urge to buy tools from Harbor Freight. Unless said tool is a screwdriver you plan to use once, my advice would be to stay away

.