Reply to SL4 or Sixty-Eight?

looking for some input. the difference in price is a huge factor (plus i have the denon hc-1000 and a working mixer, albeit behringer, already). the biggest reason i'm looking at the two are because i want the two usb connections. the sl4 would satisfy that piece of it for a lot cheaper. what i'm wondering is if the feature set you gain is worth it, specifically the recording of sets.

i've read a lot of reviews on the sixty-eight, but i'm wondering if anyone else has had to make this decision. is the 68 worth $1500 more than the sl4?