Nothing, and I mean NOTHING, will properly replicate the sound of a tube amp like a genuine tube amp will.
That said, I don't consider the Vypyr or the Line 6-Bogner amp or anything like them genuine tube amps.
They are amps with tubes, yes, but they still have a host of solid state/digital nonsense in the pre-amp section and too much modeling manipulation (heads, cabs, efx, etc...) that hinders whatever genuine tube amp tone they might have...but if you like the sounds that the amp is making, that's all that really matters.
And it's not the wattage that makes the difference in the tone of a tube amp, it's the amp design and components used....and the speaker, to a large degree. A low-watt Class A tube amp will generally be perceived as having a richer, more sensitive, 'louder' tone than a higher wattage Class A/B amp because of the amp's electronic circuit design.
It's for this reason that as I've gotten older I've moved from high-watt A/B amps to low-watt A combos.
btw: I used a Line 6 Spider II for about 10 years and I fooled a lot of people into thinking that it was another kind of amp, but I did a lot of tweaking to it and always kept the treble control down as Line 6 amps tend to err on the bright/brittle side of tone.