I've had a Vetta II Head for about a year and a half. I'm a bedroom player so I've never gigged with it but you can definitely get some good sounds out of it if you spend some time with it. (the soldano SLO-100 setting is my favorite)
I've never heard the H&K, but the Vetta will give you some more capatilities than the H&K because it is stereo so you can blend any two sounds together you want.
For gigging, if you buy a footcontroller, you can program your presets to go with the songs you play so you can play Stairway to Heaven, tap, Comfortably Numb, tap, Back for more, tap, Always with me, always with you, etc. as opposed to having to tweak individual knobs as you go like with normal heads. Of course, you can do it without the foot controller but you'd have to walk back to the head and push a button or turn one knob.
Another somewhat popular thing is to just get a Pod XTLive (I have one of those too) and run it into a tube power amp, (or PA) which gives you the same capabilities as the Vetta II except for the stereo/two amps at once feature.
If you are going to go for the Vetta II head, just make sure if you get a 2x12 or 4x12 that it has two inputs so each speaker gets it's own amp signal. I bought a Avatar 2x12 and had them wire it that way and also got two different models of speaker in it (V30 & H30) for even more variety.
The HD147 doesn't have as many amp models/features as the Vetta II does, or the two amps at once.
Give it a listen and see what you think. It's not tube snob heaven but will your audience even notice?