What about Alien Resurrection? I'd reserve the "complete garbage" title for 4, not 3. There simply is no compelling reason whatsoever for me to watch it again.
Alien3 is like the Godfather Pt.3 - if films were in competitive leagues, with Alien, Aliens, Godfather 1 & 2 all in the masterpiece league, A3 or G3 are at least two leagues below. They concluded the trilogy, ok-ish. Matrix 3 is at least another league below A3 or G3
I'd put A4 and M3 in the same bin.. I mean league.

The one with the title "if someone buys me this as a present, they don't know me very well"
Separate question - I have Alien and Aliens on DVD. I also have two 1080p screens (my monitor and my TV). Is it worth having the quadrilogy? Personally I find Alien perfectly watchable in its current format,
but Aliens is horrendously grainy. I looked at stills on a Blu-ray review site, but stills can be quite deceiving, one way or the other.
One other thing that makes me hesitate in getting Blu-ray movies is that I don't have a Blu-ray reader drive in my PC. I do have a Blu-ray player however.