Green,
Like most tools, "Best" in a CMS/SCMS is dependent on a number of things:
Usage - Will he be cutting a lot of tall crown or molding? If yes, then a 12" SCMS might be better than a 10".
Portability/Weight - Does it need to be portable? Will he be taking it to the work site? Even if he's going to use it at home, if he's going to retrim the entire house, it could be a major pain to run back and forth to to the shop for each cut. Same goes for building a deck. It would be a lot better to have it handy. For portability, weight is a big piece of this. DAMHIKT. OTOH, if it's only being used in a shop, weight becomes a non-issue.
Dust Collection - If only used in the shop, he can rig up permanent dust collection and it will probably work pretty well. If used in the rest of the home... Well, you know the routine.
Cut Quality - If he's using to cut 2X boards for a deck, cut quality isn't too important. I.e., in this situation, the miter saw is just a rough-carpentry tool. OTOH, if he's running trim, or cutting rails and stiles, he needs to consider the miter saw a precision instrument and buy accordingly.
Regarding what's on the market now, here are my opinions:
Kapex - Has received a bad rap in the pro community because of turntable issues, including scraping and stiffness. These issues appear to be resolved, but the perception remains. OTOH and as everyone here knows, it is precise instrument, that is very light, has excellent capacity, and very good dust collection. The major issue with the Kapex is cost.
Makita LS1016 ($500 - $550 street) - A brand new 10" miter saw. It has quickly gotten a lot of fans because it light, relatively quiet, has very good capacity, is pretty well made, and has some very nice features. The turntable is exceptional. It rotates very smoothly and locks solidly. OTOH, the dust collection is only fair and to get past 45* in bevel, you have to make an alignment adjustment with a screw.
The biggest issue with the 1016 is a QC or design issue - a substantial portion of the 1016's have runout (blade wobble). This causes problems with aligning the lasers, gouges in the cut surface, and the cut is not as precise as it should be. For some folks who have had this issue, it's a concern. For others, it's a showstopper. IMO, it's a big issue.
Milwaukee 6955-20 ($750 street) - This is a relatively new 12" saw. I don't know much about it, but it has received excellent reviews. Dust collection is supposed to be excellent, capacity is exceptional (cuts 6 1/2" vertically), and has a digital miter readout. OTOH, it's very heavy. Weight is listed at 65 lbs, but I've been told it's actually over 70. WAY too heavy for me.
Dewalt 717 (about $600 street) - Very new 10" miter saw. Has received good reviews. OTOH, the stock blade is apparently mediocre so you to get a new one. And the biggie is that it's a Dewalt. I'm biased; I don't buy their saws any more.
I know a fair amount about the Makita LS1016L because I bought one... And took it back because of blade runout. The replacement had blade runout too and was noisier than the first. So I returned it too.
Since I'm VERY tired of hassling with problem tools, I just ordered a Kapex. I hope I made the right decision.
Regards,
Dan.