I've had mine for almost 2 weeks now, based on my experience so far I'd say go for it, you can't go far wrong for the money.
Only problem so far is the standby battery drainage, I'm seeing -4% an hour on average, it's unacceptable in comparison to the drain during use. However, it seems the problem is with the EMEA 1.6 software, the Asian version does not have this problem. Acer_Liquid_2.000.16_EMEA_GEN1 has already been leaked on MoDaCo, so possibly we'll see an update from Acer soon with the issues fixed.
I purchased from a UK ebay seller for £288 unlocked, and I'm using O2 pay and go with the web bolt-on, £7.50pm only allows you 200MB data. That covers all email, and a fair bit of web access when I'm not on campus or at home with wireless to connect to.
Take a look at my posts in here, it might cover some other questions you might have Wondering whether to get the Liquid
Apparently Acer are releasing a number of Android phones this year, so it could be worth waiting.