I use Upmind since I started using Enhance and had no issues so far. Yet I find the comments here about Blesta very interesting and I am tempted to consider it as well in the future due to data own/privacy reasons. For now I'll stick to Upmind as it's easy to use, it was super fast and easy to setup and has a modern UI out the box. From what I can see, Blesta requires separate templates to be purchased and some configuration and potential dev time which I cannot afford to do right now.
So if you want something fast to setup and use, with a modern UI out the box ...
Also Upmind has a free version which you can use with quite some generous limits.
Also, it's not dead, I found they do update quite regularly and their support is very responsive.