Their program is credit based so it is probably more rewarding for the short haul traveler. They don't have any redemption partners except for Frontier but will buy you a ticket on OALs for at certain credit levels.

One-way Business Class upgrade 4
One-way coach ticket 8
One-way Business Class ticket 16
Roundtrip coach ticket on another airline in the contiguous 48 US states 32
Roundtrip coach ticket on another airline between the contiguous 48 US states and Alaska, Hawaii, Canada and Mexico 50
Roundtrip coach ticket on another airline anywhere else in the world 100
Free* annual companion pass 100
Travel on Frontier in U.S. and Canada 24 A+ Rewards Credits*
Travel on Frontier to Mexico and Alaska 36 A+ Rewards Credits*

I'm sure they would create some conversion of miles into segments. My guess from looking at their program and knowing Midwest's is that it would be 1500 miles = 1 credit.

The Air Tran credit card is also issued by Juniper/Barclays. I suppose a quick way to build up lots of Air Tran credits would be to get the YX card (and business card) and also the Air Tran credit card before the merger happens.

22500 miles for YX credit card (bonus + balance transfer
22500 miles for YX business credit card (bonus + balance transfer)

16 credits for Air Tran Visa (bonus + balance transfer)