I have the Alpine. Love it. Screen isn't an iPad quality, but it works a million times better than any other car radio I've ever had. (see my pic in the purchases thread). Was installed by SSV Thomastown.
I encounter occasional bugs with apps like PocketCast (usually when starting a podcast) but it's generally rock solid. Siri can be a bit hit and miss (as she always is) but if I have strong cellular signal, the dictation is amazing.
Highly recommended. Has made an hour commute downright pleasurable. I love Podcasts in the car + Siri messages, and the calls interface is great, especially if you have Visual Voicemail on your phone plan. Seriously - if you spend a lot of time in the car, do it ASAP. You won't regret it.