Patches and reinstallation capability would be my big concern here. I have the games on my computer, but they aren't running properly and I've lost the old disks. Can you reinstall the games if you need to? Do they come full patched / at least have patch capability?
If so, I'd probably drop the cash. Tactics aint so hot, but Fallout 1 and 2 are definently worth the price.
Then check out http://www.gog.com. They're DRM free, and once you purchase them you can re-download at any point. I lost my original FO2 disc (have the manual, go figure) and was pleased with the ease of installation from gog.com. Not bad for $6. If you're super-paranoid about losing the game, you can burn it to a disc for safe keeping. And the games are patched to the latest version. I installed killap's Fallout 2 restoration project unofficial mod and the hi-res mod without any trouble. You can get some cool swag like a PDF of the manual, desktop backgrounds, music, and avatar pics. So in other words, I had a positive experience w/ that site.