In the kind of setting I'd tend to play in, guitarists are rarely using more than a 1x12 combo, drummers usually have some subtlety and there are often multiple vocals or acoustic instruments that necessitate keeping the stage volume reasonable. In that environment I've found that a 100 watt valve amp through a reasonably efficient 2x12" cab was always more than ample. So I'd expect to push a 50 watt amp a little more, but that should be a fun sound anyway. With that in mind (and experience with several valve amps from 40 up to 100 watts), I'm pretty confident that the Pf-50t will work for me.
If your guitarists and drummer have more rockish tendencies, then you'd probably want a little more.