Just to balance the scales a little bit - I rode an Kona Four Deluxe with semi slicks to work for years and I still maintain that it was the best commuter bike i've ever had (Obviously I used it off road as well recreationally)
Soaked up the bumps, and was versatile enough so that I could detour if necessary, go through parks and have a bit of fun.
I was gutted when the frame cracked (Scandium construction and on the seat post weld, so not an easy repair weld - 1 month out of warranty too). Unfortunately I'd already bought a racer (Giant Defy 2) as a ride to work bike when I moved out here - something I regret as I never really got on with it for the couple of years I commuted with it.
Rather strangely the Four Deluxe wasn't any slower than the Defy in terms of commute, due to the terrain, poor road surfaces and traffic - you could simply attack the journey with the Four Deluxe, keeping an eye on the traffic and not the road surface. Bob wise I ran a reasonably high shock pressure and did use pro pedal on some hills, but whereas bob was noticeable, I honestly didn't find it that bad. Perhaps due to the relatively mild 2-3 inches of rear travel.
I've also suffered with recurring lower back problems/sciatic nerve problems before and never had any grief when I was using the bike - not saying at all that it will be the same for anyone - I could well be the exception.
I'm not suggesting that anyone suggesting otherwise is wrong - just that I got told exactly the same thing when I bought the Four Deluxe and I went against the grain. I tried to be as sensible as possible with it though - being a lightweight, low travel, full suspension bike with lock outable suspension and not some crazy freeride monster - that would be a bit silly!
Huddy - I got mine as a clearance job from jejames cycles on a ride to work scheme - they had a lot of cheaper full sussers - less so now - but there are a couple of giants for around your budget. I'm not up to date on specs and so i'm not aware of the pros and cons of 29er and 27.5 would be for your usage.
Good luck!