anybody used mobile broadband for VO in the EU/UK, and if so, how well? massive lag or no?

It's not too bad, as long as ye stay away from BS/HS/NW

I dunno about EU/UK, but I used 3G and it's slower cousin several times while I was a longhaul trucker here in the USA.. And yea.. combat over 3G is.. while better than the CDMA connection, still not much better latency-wise.

General rule of thumb for average latencies: best to worst.

DSL (both SDSL and ADSL, if you aren't sure, you likely have ADSL) 30-80ms
Cablemodem 95-150ms
Dialup 300-400ms
3G cellular varies a bunch, in the same connection.. might be 300ms one min, then 800ms the next.
CDMA is about the same as 3G (main difference to 3G is bandwidth, ie download speeds)
Satellite 800-900ms