convenience and comfort goes to the high-speed in my book. i would rather ride up 2000+ vert on a high speed lift than sit there and freeze my ass cheeks to the seat on the 20 minute ride. but when it comes to uphill capacity, fixed and detached seem to be similar from everything that i just looked at.
you can buy them new for $150 on dogfunk and some other sites right now. i would lower your price since they are used or you might be holding onto them for a while.