Electrical tools generally cost a good bit more, and their life can be short if you use them hard.Brushes burn out, armatures short out from metal filings etc . Air tools can be had cheaper usually, and seem to run forever with proper care (generally just a shot of oil now and then). No brushes, magnets or any of that stuff. You can also plumb your shop to have air hook ups just like electric, bout like running conduit anyhow it just has to be air tight and hold 150 psi or so.
Trouble with air tools is you have to have quite a compressor (something in the neighborhood of 10 cfm at 90 psi) to run anything with them. My dad has a 5 hp 25 or 30 gallon compressor (might go about 5 cfm at 90 psi) and its pretty much a joke to try and do any serious work with it on a rotary type tool (sander, grinder, die grinder, cut off wheel etc. ) You get good speed out of it for a few seconds and then you're waiting on pressure to build up again.
And because you need a huge compressor to run them, you don't really get much use out of an air tool outside the shop. Its not too hard to drag out extension cords, or even a generator, but a 500lb air compressor is a different story
So if you can get a big enough compressor, and plan on mainly using them in the shop, I'd go with the air tools. If you plan on using them outside the shop much at all, then I'd go with electric (except I would stick with air powered nail guns, impact wrenches, and other stuff like that where you don't need such a high volume to run them)
