I'd avoid the pistol, it's pretty much just a gimmick unless you want to go through the SBR hassle.
I also would not bother with optics on an AK.
If you get one that will take the side mount scope a red dot should work. It won't make it more accurate, but it should give faster target acquistion and help in the dark. Plus if you've got old eyes it can't hurt. One advantacge to the AK over the AR is that since the optic is off to the side you can transition instantly to the irons.
As far as buying one, I would. I just wouldn't spend much, if anything beyond six bills for one. They are what they are. Just make sure yours doesn't have sight cant issues and will handle single and double stack mags. Its a fun toy, good for SD and if you buy a five round mag its the same as a 30-30 for bambi.