I don't know about all of the Suntour forks, just the cheap ones, but I've used two kinds that I know of.
I have two identical Suntour something-2000 black steel forks, one of which I welded a disc-brake mount to, the other of which is still as-is. The former has been used on CrazyBike2 for some time, I forget how long but maybe a couple of years (EDIT: more like 3-4 years, after reviewing posts in my CB2 thread) total (not counting the long break starting a bit before the housefire till a few months later), and it's still mostly ok, even after a couple of crashes (one during the DeathRace where I broke my ankle), and I haven't screwed up the dropouts yet, even with regen and accel on a 26" 9C 40A 12FET all the time on my daily commutes. The bushings (nylon? dunno) between the inner tube and the outer fork itself are wearing, as the fork rocks back and forth there if I hold the brakes and push the bike forward or backward. I'm sure they could be replaced, but I haven't tried taking the fork apart to see.
Now it's on my trike, with an X5304 (no torque arms yet) on a 33A controller (no regen yet, and apparently "soft start"). Still havent' screwed up the dropouts, but it probably would if I used it with the X5304 and regen and hard start with the 40A unit, without torque arms (the axle isn't long enough for them).
The other one, I cant' remmber but I don't think I've used it yet. I'm sure there's info on it in my CrazyBike2 thread, but nto sure where.
EDIT: found the post:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=954759&hilit=suntour#p954759
it shows both types of fork, the steel (black) and the alloy (white).
I also have a suntour xcv3 alloy fork, no rim brake bosses, just disc, but I added my own with hose clamps/etc (see the crazyBike2 thread and search for "suntour" in it for the posts about that). It's a lot better fork than the other one, but being alloy, I wouldn't trust the dropouts without torque arms. I used wrenches, and so far it's survived fine on CB2 with the same usage the other one had, but it's only been on there a few months.
FWIW, if axle length permits, I'd *always* use hefty torque arms on any front hubmotor, regardless of how good the dropouts might be rated or experienced, unless you actually built them yourself as pinching/clamping dropouts with as much axle-flat-mating surface area as possible given the axle length.
If you wanna use your existing forks, you can look at a thread from this week where John in CR responds to Cwah with a way to fix his broken dropout fork. That's how I'll be fixing some Manitou Skareb forks I screwed up, someday when I have time/materials.