I tried a Terra.
It had to go back because of many faults.
I was also really disappointed with the build quality for such a premium product.
Initially I asked for a replacement, however there was no remaining stock of the terra in the UK so I just got a refund. I didn't bother with buying another one after the experience.
It doesn't really provide anything more than what you can create yourself at a fraction of the cost. Also I've never been able to get any kind of explanation about the lifespan of the UV in the cold cathode tube and if / how these are replaced.