psybox To be honest you're wrong, Blesta does have support area baked in out the box and Knowledge base. As for Registrar/domain management it's just a module away as far as I understand - due to needing to know which vendor(s) you're using. There's also tools for migrating from WHMCS for example... So none of these points you raised are true.
I am very new to my Blesta setup, but I instantly see you're wrong on most these points.
Upmind is closed source, slow on updates/tickets and hasn't gained the best reputation on here... which is why I waited sometime before choosing a panel and Blesta was the best value for money, also, being backed by Philips was another selling point for choosing one over another. The only thing I see going for Upmind is it's pretty... Nothing themes can't fix with Blesta.