Um basically I am new to the genre. Soul Sacirifice is like one of the coolest things ever to me so I wanna check out other games. Im not very picky and money is not an issue. I just asked if there is other PSP titles on PSN for the genre. I am WELL AWARE of the VITA games out and coming out.
I would recommend Peace Walker as your third purchase. While not 100% the same as MHFU and GEB. It's still a hub mission based game with a military tone that's a great game that might prevent you form getting burn out on pure monster hunting.
How would I love to tell you to grab Phantasy Star Portable 2 but its no longer with us.