John's right. Personally for me I went with a 8120 because I hate the bigger footprint of the Curve. The rest of my family went with the Curve and laughed at me. Personally I don't regret the decision I made one bit. Do your research and make a decision.
Do as Penguin suggested and check them out. The differences between 88xx devices and 83xx devices are mainly no camera on the 88xx devices. All devices that end in xx20 are wifi devices. They all work the same so none is better than the other. They just do different jobs. You need to know what you need and choose from there.
I have an 8120 and just recently grabbed the 8310. I love the wifi on my Pearl but it hasn't been anywhere near as useful as the GPS in my Curve. I've also noticed that my Curve seems a bit more responsive and the camera and video camera seem to be of better quality. I've used all sorts of diff OS versions too. Also, I totally dig the wider screen and not having to add custom words because SureType doesn't know all words.
ill edit main post if someone could give some good an bad? really want to order soon
In other words, "good" and "bad" are defined by your needs/wants versus the features of the devices in question. Compare the features & pick the one that suits you best. You haven't posted what you want or need so we really can't even make a meaningful recommendation.
I agree with everyone. You just have to go with what you want more out of a phone. If you like GPS, then get a phone with GPS. I have an 8320 and I love it! It's great because you can do sooo much with it. The WIFI is a plus for me because it's a free phone call when I'm connected to any WIFI area. Plus I'm with T-Mobile so I get my 5 Faves on top of that. I love the full QWERTY keyboard. I hate the QUICK text idea....eww. Just see each phone and what it has to offer and look into what YOU want the phone to do.