Those reviews are not very helpful for us (astronomers).
Poetic language used is very often misleading and based on this you can't possibly decide which lens is better or even adequate for astro-work.
The only relevant info for the lens quality may be in a form of MTF - and this is shown by manufacturers less often than snake's legs.
The only thing I can advise is, try to borrow from someone and perform a test on stars, then buy.
This page can be helpful..
http://www.astrosurf.com/~buil/50mm/test.htm
http://astrosurf.com/buil/us/10d/testopt.htm
I have a good experience with Canon 50mm F1.4 FD lens (but I had to mechanically modify it to fit my Canon 400D, and it is not too hard to do).
Also, I have Itorex 28mm F1.8 (originally for Pentax or Praktica, with M42 mount), it is very sharp when used at f2.8 or more - and very good for astro work (but 100% manual, of course).
All those were around $100 or slightly more (but well below $200, on ebay).
You may also try to have a look at
www.rugift.com
Nikon lenses are considered very good for astro photography by many (and Nikon->Canon EOS adapter is very cheap on Ebay, as it does not have any optical and/or electronic elements, it just provides necessary mechanical interface between camera and lens).