I've tried out 3 different covers on my truck already in the year that I have now owned it. I started with a cheap Gator brand soft roll up cover. It wasn't bad for the price, but wanted something a little more secure for when we traveled. Stepped up to Gator EFX hard fold cover next. It was an all around nice, solid cover. Only changed out from it to get one that would open all the way up for full bed access. I recently got a Bakflip MX4 based of some of my buddies having them on their previous trucks. I've got to say, I'm not very impressed with the new MX4; it is made way cheaper than what they used to be compared to what my buddies had. It feels cheap, and the side seals on it constantly pop out of the joints where the panels fold. Also seems really stupid to not have one of the panels latch down, I can get my finger under it from the side and lift up and gain bed access. Also the latches aren't super tight, leaving a lot of slop in the panels. Not impressed at all for the price paid. The old Gator was overall better quality.
Been looking at Roll-N-Lock and REtrax covers recently, as well as Agri-Cover Lomax Stance as replacement. I can't quite talk myself into going with retractable though. May go with the Lomax Stance next. Granted this is my experience so far on a standard bed truck. I think I'd have a totally different outlook if I had an 8' bed. Like you mentioned; a hard fold on an 8' bed would probably be pretty hefty to mess with. Paragon's are pretty nice also, may want to look into them as well.