I use a Triaxis and 20/20 almost everyday. It is loud enough for a band and can power 2 - 2X12 cabs with ease. Just don't expect the same tone as the 20/20 will have a different sound than your 50/50. The EL84 tubes will reach their limit much quicker and won't have as big of a bottom end than 6L6 tubes. If you need thump at huge volumes then fuhget about it. Most bands have a PA or play at venues that use a PA so micing your cab is always an option if the 20/20 isn't loud enough.
I guess without knowing your situation (your tone requirements, band situation, loudness level, etc) it's hard to say whether or not it would be right for you.
Greg