Umm i think there are only one or two folks who have heard the HE-5 on the EF-5 so it is much too early to call for a consensus.
I can tell you though that this SOHA-2 will kick some serious butt in that price range. It will power the HE-5 and sound great with ease. It can drive my Wharfedale ID1 means the HE-5 is a piece of cake for it. I have heard the HE-5 on this particular SOHA-2 and can't recommend it enough for anyone looking for quality amplification.
edit: yes I am listening to this amp right now