It all depends what you need it for.
I started off with just a Craftsman 3/8 drive 20-150ftlb "foot pounds"
Well then I needed to torque a bolt to 170.
Got a 1/2" drive Mac from the pawn shop that goes 35-250ftlb
Needed a series of 6mm manifold bolts torqued in inch lbs so I got a 3/8 drive Craftsman 20-150inlb "inch pounds"
I wish it were 1/4 drive
Needed a bolt torqued at a funny angle and coincidentally came across an Armstrong flex head 3/8 drive 20-140 ftlb for a Benjamin
Getting a new job and having two full sets of tools now I had to get another 1/2" drive beater craftsman torque wrench
Bearing preloads can't use clicker type wrenches so I have a 3/8 ftlb beam torque wrench, a 1/4 drive inlb beam, and a bigger sk dial 0-600 inlb 3/8 drive
The other day I needed 450 I I got a cheap powerbuilt 3/4 drive 50-600 ftlb and it seems real nice for the price
I was out on the road a while back without one and had to buy a walmart one to get me by too!
The takeaway here is no matter what brand you are looking for, every brand makes a variety of combinations of wrenches. Make shure your choice covers a broad range of torque and the drive size is the best fit for what your using it for.
General snowmobile engine building is mostly 3/8 drive, except for the magneto and clutch which are definitely 1/2. Well if your real anal about all the 6mm bolts that would definitely take a 1/4 drive inlb.