I have a slight astigmatism, but apparently not enough to cause issues with a red dot, at least with contacts, anyway. I actually did not know about the astigmatism issues before buying my Aimpoint, to be honest - so I feel a bit lucky.
I have a T1 Micro on my AR, but recently bought a PA Micro for my 15-22. The PA Micro is a very popular "budget" red dot, but I do have a few issues with it. With all the PA love this might be an unpopular post - and while it's not at all fair to compare it to an Aimpoint at 1/5 the price, there are some noticeable differences. The emitter is very prominent coming from the T1, but I can live with it. The battery cover is the same width as the dial, so I sometime find myself unscrewing the cover as i turn up the brightness. The dot is not as precise (different MOA which is part of it), and the optic is noticeably less clear/bright, esp indoors. The dot blooms much easier/quicker than the T1 as well. Oh and the QD mount is absolute ****. The packaging was a bit iffy - just loosely rolled in some bubblewrap in a box, vs custom molded foam for the Aimpoint.
As stated, not fair to compare it to the Aimpoint Micro, but I see threads where people claim the PA Micro is 90% of the Aimpoint at 20% of the price, but I just don't agree. If you've never used an Aimpoint, then most of what I listed above probably wouldn't be noticeable. It's a nice value unit, and a solid choice over some of the cheapo brands listed earlier in thread for sure. I will say I used an UTG Red/Green dot for a bit and found it to be just as nice as the PA unit, if not nicer. It's just a larger unit and I wanted the smaller unit similar to the H1/T1 form factor - otherwise I would just leave the UTG on my 15-22.