SE Vivaz or wait for the Xperia X10?

[Zippee]

I'm after my first smartphone and have taken a shine to the SE Vivaz which I can have now with Vodafone for £30 a month (600 mins, unltd texts and internet), alternatively the new X10 looks even nicer but Vodafone have no release date yet and can't give me a price or tariff until it's actually available.
Question is though just how much better is the X10 likely to be over the Vivaz? The Vivaz has gotten some very good reviews and scores highly on GSMArena.com.

Any opinions?

[andyps]

I was going to go for the Xperia having had SE phones for many years. As a smart phone I think it will be much better than Vivaz which is more a phone with a touch screen than a true smart phone in my opinion - essentially it is Symbian OS rather than a full smart phone OS which the Xperia has with Android. However, I have now ordered a Google Nexus One because I decided I might as well get the pure and easily updateable OS which that will provide - I got concerned that SE are only using Android 1.6 at introduction and not giving much indication of how quickly they would get up to date. I am sure it will work well and have a nice UI according to the info available so far. Release date looks like end of this month from everything I have seen.

I just hope I am happy with the Nexus camera having had an SE C905 with 8.1mp resolution and all the camera gizmos SE provide.