The Velocity is designed to be a fast boat in flat water. The pad makes it that way, but its going to cost you rough water ride comfort, and I am willing to bet you don't see much rough water up there off the coast of New Jersey.
The Pantera is a true old school race and time tested design. No qualms about that. However, outside of a large cockpit for its size, the boat doesn't really have any creature comforts. The 500EFI is a great motor if you want to do HP mods, but I don't think that is a direction you want to go.
The AT is going to have a slightly smaller cockpit than the Pantera, and it will feel that way as well due to the freeboard of the AT. You are IN the boat, not ON it. This will lend to a more secure feel in rough water; and have a feel similar to your Formula. With the 525EFI, expect 73-75mph. The cabin is designed with headroom and comfort in mind; and a separate head.
Cosmic12, Boatfreak, and Commander112 can all share real world experience in the 28AT.
Cosmic had an identical boat with a 525EFI.
Commander112 has one with a 500EFI, that he just bought this summer and LOVES it. He has done some carbon fiber upgrades and the like, and it looks great. Its a wave crusher.
Boatfreak had his 28 for 6 years with a 496HO, and he has run all over the midwest including Lakes Michigan and Cumberland, all the way to the Florida Keys. Just this past January, he went with a party of 7 other boats which were all 33 and 37 ATs, and one 50' Hustler down to Key Largo and Islemoralda, which was 250 mile round trip. Not only did he not have any problems keeping up (with a 496HO mind you), but he had no issues when the water kicked up to 3-4s off of Key Biscayne.
BTW, OSO member 'risky' aka Vic is selling his 28AT (the one linked above) to get a bigger AT.
We sold Boatfreak's aka Mike's 28AT in two weeks this summer so he could move into his 37AT.
Good luck, and let me know if I can be of any more assistance.