Terry Allan, I've never had feedback problems with my system, and I stand about 3 - 4 feet in front and to the side of my unit. I didn't notice the hiss you were talking about. Did you use the remote controller for EQ and volume levels?
It doesn't have reverb, and I don't miss it.
Each room has its own natural reverberation, and in my opinion, artificial enhancement is not necessarily a good thing.
My take on the Bose PAS is that it has the effect of the musician playing and singing acoustically in a room, as he/she would at a session, without artificial reverb, naturally - just louder so everyone can hear.
I've been through a shitload of PA systems in my 34 years of professional performing, as I'm sure you have, and I like this one best.
However like a lot of aging musicians, if someone comes out with a smaller, lighter, more easily portable yet equally powerful system, I'd probably buy that!

Seamus