I think ampharos is more annoying than effective. I played one tonight with my resh deck, and yeah when I attached the extra 2 energies a turn it sucked getting 2 counters, but I run with typhlosion anyway, so it's only one more counter per turn. and in the end reshiram can hit pretty hard with a lot of counters on it. my opponent had to spend time getting ampharos out and evolved so after I KO'd his main attacker, he just then got his second one out and starting building it, and ran out of time. the second time I played him, he didn't have time to even get his second out before I KO'd his first, then took out his ampharos the next turn while he started to build his second guy, and then I KO'd his second after I switched to my second resh healthy and ready to go.
that guy usually beats me too, but tonight he tried ampharos tech and lost both times. you'd have to really have the perfect t/s/s in your deck for ampharos to be able to be a tech.