It looks like the Solana was made by Hot Springs, many people have spas by them that are over 10 YO. I know nothing about that spa but ...
If it is running then you could take a chance on it. Make sure it functions the way it should - pumps run, heats the water and anything else it is supposed to do. AND doesn't leak!
I have a 2005 tub that is in great shape - it isn't brand spanking new and needs a couple of new jets, I have repaired a leak and a pump seal and it needs another repair but it is 10 YO.
I suspect that it's 120 volt which means it'll heat slowly, not be able to maintain heat if the pump(s) are on if you're outside soaking for a long while but it should be able to maintain heat for a 20 minute soak (pumps can and do generate some heat). As far as energy efficiency, it's a small tub and I don't think insulation technology has changed much since 2002 so it'll be about as efficient as any other smallish tub IMO as long as it still has it's insulation intact.
Oh, one last thing - cover - they can cost a few hundred bucks so if it's not in good condition you may need to buy one.
Hopefully this helps!
