MO - Missouri
I mainly play Legendary solo and it's amazing.
Conversely... I am considering Sentinels. Is it good solo?
I agree about Legendary solo. The only downside to Sentinels solo is that you have to play multiple characters. It's not that difficult, but it can get a little overly fiddly for one person to keep track of it all, I think. Your mileage may vary.
Also, Sentinels and Legendary are nothing alike gameplay-wise, so don't go into it expecting a similar experience. I think they're both great games, but outside of theme and the fact that they use cards, there's basically no similarity.