That's definitely why you do not shoot at the same spot once you get some time in. Group shooting may look good on a picture or to other people but it sure can be expensive.

Will the speed difference be that great if my draw length is only 27"? is the quality of the bows any different?

Typically the shorter the draw the slower the speed.

There are a few bows out there that are designed to stay up in the 300's with short draw's. Just look them up. I think that BowTech makes one.

I owned a Liberty back in it's day but I have never been fond of Single Cams. Although the Liberty is a nice bow, I would opt for the TomKat to get the Binary Cam technology