I’m “Old School” but fairly open minded, I just can’t seem to warm up to the new style Carbine buttstocks. I use Mil spec tubes and the earlier buttstocks on every M-4 I build, but I’m considering the new style for my next build. Any pros to the newer buttstocks vs the earlier type?
Well the new style ‘M4’ stock offers a longer buttpad and the Vltor offers better cheek weld over the original style. I’m a bigger guy, 5’ 11" 230lb, and I prefer the newer style stocks. Have both the newer M4 style and the CTR on my carbines.
Now my wife, 5’ 4" 120ish, prefers the original style and the Vltor as they are smaller in the butt over the ones I use.
That old style stock means you need to hunch down onto the rifle for a good cheek weld. The newer style gives an extra inch or so to sit in the shoulder allowing a more heads-up stance.
Those older ones do look cool, though. 
Pros would be better ergonomics, cheek weld, more durable construction, quicker deployment. Take a good look at the magpul ctr. It’s really quite hard to beat for a carbine stock IMHO. Especially for the price.
The below link gives a brief overview of various carbine stocks, it may be of some help.
For a light weight carbine, I haven’t found anything better than the Magpul CTR.
SOPMOD, Vltor, CTR or even the M4 Type II are better in my worthless opinion than the old style M4 stock.
The Old style M4 stock is all I roll with, Son! But I’m not a lanky goon, so I match up to it pretty good.
I can’t even get into the New Style Colt OEM stocks. They just seem so big and bulky.
If you want storage compartments for batteries etc., and a great cheek weld VLTOR is great!