I have done kits from ToTW, Chambers, and now a Kibler.
Without a doubt, the Kibler SMR kit was the easiest to put together. I would not even refer to that as a "build"....it's more of an "assembly." Barrel/tang...snap fit...and I mean a SNAP fit. Went in well with excellent inletting with no gaps. Lock plate, a tiny amount of scraping on the mortise. Lock internals....a tiny bit of extra wood removal for a couple screw heads. Butt plate....filed the contacting surfaces a bit...then fit with no gaps. The set triggers required a little more work to inlet....just use some inletting black. Trigger guard a small amount of inlet touchup. You do have to do filing, sanding, finishing on metal parts. Without sanding or finishing, I had the SMR assembled in a few evenings and a Saturday. It took me longer to put in the patchbox I added, which included making my own springs, than the basic assembly! Of course, it was about a week and a half for final shaping, which isn't much, and finishing due to drying times etc.
Two of my three Chambers kits were not very good from the standpoint of the stocks...some inlets too BIG, burned wood because of dull power tools, etc. The results can be great...just a lot of work. My third Chambers was the Haines kit...very nice. I'd rate that a better than average kit...in the end I didn't build it because I decided I wanted a lot of carving and engraving to match an existing Haines, and I don't have the skills for that. Dave Person did the actual build and had commented that some parts were not really correst for what would be seen on a Haines.
ToTW kits are what I would call average kits....at least the two I have done. I'm sure I had over 200 hours into each of them, but I'm kinda slow.
Net...the Kibler is the way to go if you want the least amount of work to get a fantastic result.