To punch through in a live situation you still can't beat a valve amp but they do take a bit of looking after and are basically still a little unreliable. REGARDLESS of how much money you spend, valves are consummables, so even in a £2000+ Mesa or Soldano it's the valves that are the heart and soul but also the weak point. Don't get angry or upset if they let you down at a gig, just be prepared and learn how and what to change. Have a spare set of valves and fuses, let your amp warm up and cool down, use the standby and be careful in transporting it etc etc. Otherwise, personally I would say go with a solid state amp like the Mustang range, until you HAVE to go valve.
Finally, I know this is a website and we do sell online and ship worldwide but really, unless you are very experienced don't buy a valve amp online, buy local or drive and pick it up. See it in store working first too which means don't buy an un-opnened one in a box.