It's hard to provide advice without knowing what's important to you. I'd check the reviews at http://www.eham.net/reviews/
before buying anything.
I can say that x-band repeat is way overrated. It sounds cool, but it's generally not very practical. It's usually complicated to set up, and there's the problem of ID-ing your repeater. When you transmit your call, on UHF and your repeater retransmits the call on VHF, you've identified your handheld on UHF and your mobile on VHF. When the other station comes back with his call, he's ID'd your mobile with his ID on UHF, not your ID. I suppose you could call your mobile on VHF to get your ID to come out on UHF, to be legal, but that's a little awkward. Likewise, you could hook an IDer up like repeaters do, but that's also some hassle.
Then there's the matter of power. If you're using this to have a mobile repeater so you can work from your handheld, you'll probably want an extra battery if you're leaving your car unattended. It would suck to come back to your car after a day of wilderness QSOs only to find your car battery was dead.
All this (and more) might be worth it to you, but it's not to most. I will say that listening on two channels at once is handy. Making sure you pick the right band to reply before keying the mike can be a bit of a distraction if you're driving, however. For me, I tended to use just one band for talking and the other more for monitoring to avoid that confusion.