The Teleporter is half the resolution of the Predator. So you get a lot less fidelity and if you try flying with an OSD it will likely be unreadable.
Otherwise the goggles themselves appear to be more or less identical based on the spec sheets from FatShark:
Predator V2:
Display
Full color Kopin CyberDisplay
922,000 pixels binocular display (640 X 480 VGA)
NTCS/PAL auto selecting
Teleporter V3:
Display
Full color Kopin CyberDisplay
230,000 pixels binocular display (320 X 240 QVGA)
NTCS/PAL auto selecting
Full spec sheet for Predator:
http://fatshark.com/uploads/pdf/1719-2.pdf
Full spec sheet for Teleporter:
http://fatshark.com/uploads/pdf/1756-2.pdf
The cameras they ship with are also somewhat different. The specs on the Teleporter camera sound a bit lower than the ones on the Predator - but the Teleporter camera can record while the Predator camera can't.
They both use the same RF system.
I went back and forth quite a bit and ended up deciding against either and going with the Base SD (ordered from getfpv whom I was VERY impressed with the service from.) The downside there is that the Base SD is almost as expensive as the Predator but doesn't include the VTX/RX or camera - it's just goggles. I already had a 5.8g TX/RX set I was experimenting with and my long term plans include 1.2/1.3ghz instead of 5.8 so the RX in the goggles didn't seem that great to me. The Base also has a 35 degree FOV compared to 25 with the Predator and Teleporters so it should give a more immersive image. The base also includes additional filtering to keep your RF signal from interfering and adjustable lenses to accommodate a wider range of eye positions and supposedly has better optics (glass instead of plastic.) So I figured they'd be good for me while the Predator or Teleporter would be somewhat wasteful as I didn't need or want another VTX/RX or camera.
The Base set I got is all I've got to try but I'm shocked that people are happy with Predators if their optics are any lower quality. I'm really picky about that kind of thing but the chromatic abberation on the Base goggles is really bad at the edges. And the 35 degree FOV is nice and immersive...but...it's almost too big as I have to keep looking around the image to see all of my OSD. I'd love to meet up with someone with some Predators to compare head to head with sometime.