adapters.. fish eye ?

http://www.adorama.com/PRO835EOS.htm...54059061058605 any comments or reviews on this lens.. im looking for a manual focus fisheye by one of these companies for my rebel xt. i saw a few before that were as cheap as this that were manual focus but high quality and dont remember the name. ANyone use these? or recommend others... or any new thoughts on lens adapters that look like fisheyes? also ones such as bower 8mm, falcon, sanuyung, etc. How are these? is there focus conformation? http://www.bhphotovideo.com/c/product/635178-REG/Bower_SLY358C_SLY_358C_8mm_f_3_5.html

as an update how about the other lenses by bower?

hey, I posted a question about Bower lenses somewhere on here. In general the points are they are mirror lenses which results in odd bokeh, lower IQ, and only one f stop (ie if it says 6.3 that is your only option.) Also they are all manual focus. On the positive side they are small light and cheap.

The ProOptic and Bower 8mm f3.5 Fisheyes have the same specs and look the same. I assume there is no difference between them other than name and price.

specifically, the fish eyes, how is the IQ or manual focus? anyone use one? how about on a crop such as my xt?