Are they any good for the likes of spring compressors and stubborn bolts?

Pat...

not so sure about 12v but i got a couple of 18v i use, one snap on that i have at work and a sip that i use at home, the sip seems to actually have more torque to it but the snap on has a far smoother action, when fully charged there's not much either of them won't shift.

Sorry - should have said the 12v one is powered by car battery, not a re-chargeable.

Pat...

Have used the 12V one.

Doesn't work like a normal impact wrench. The motor spools up and then it hammers at a frequency of something like 0.5hz.

It worked for removing the hub nut on a Rover 214, I know that much.

Ive got 24volt one its great only 65 quid not sure what make, will have look tomorrow if you want, kev.

I use a Makita at work an it is brilliant. You should use proper impact sockets with all impact wrenches, but for normal work a good quality socket seems to be ok.

I had one of those 12V impact guns which connected to the battery. Fell apart
Did get a replacement but don't rely on it..
Now use a pneumatic hammer gun (my friend "nutty"!)

i got an elcheapo one from woolies had for years
ok for wheel nuts but not much use for anything else tends to snap off rust bolts

12V is the 1 beat per 3 seconds one? I have one and also a cheap 18V one which has multiple beats per second. The 12V has good torque if you let it load so it's great for getting those nuts off. Only the nuts you can't get off with a wrench or else it's not worth it looking at how slow it works. It does get the job done with some patience. It's way cheaper than airtools and it's more compact and makes less noise. The downside is simply the low BBM. You won't be able to tighten it right, just use it for nuts and bolts you can't remove with other tools.

The cheap 18V I have is great. More BBM so you can get bolts off in no time. I can tighten them decently, but it doesn't have that much torque. It still is good enough for most work. Especially with a kitcar that hasn't got rusted nuts etc.

The good quality ones are excellent --- at a price £150 to £200+