Canon EF 17-85 vs Tamron 17-50 VC

Hey guys!

I need some guidance here.
I recently ordered a brand new Tamron 17-50 VC at work but haven't picked it up yet (good price for Norway, about $540 US) but now I have a chance to get a used 17-85 for 340$ US.

I've heard a lot of bad stuff about the 17-85 in terms of distortions and IQ but never used one. The Tamron on the other hand I've tried (Nikon mount, but still) and quite liked. A review in Digital Photo (UK-mag) gave the Tammy a pretty good review as well when they were comparing fast normal zooms..
I plan to shoot a lot of semi-low light with flash (I guess I'll have to anyway), so the Tammy would be great here, but the extra FL and for 200$ cheaper the Canon seems pretty damn tempting as well. It's going to be used as a walkaround for the most part, I have a 50/1.4 for most of my lowlight work, but to be able to shoot somewhat low light without lens change would be great.

How are your experiences with the 17-85? I've seen some BAD reviews, but dpreview for example gave it a pretty good review in terms of IQ at least.
Also, those who have the tammy VC, are you happy with it or do you miss abit in the long end?

Thanks in advance!
Alex

I had 17-85 before, now have 17-50 VC. Both are ok , actually I like them both.

17-85 focuses faster for sure, and more flexible for walkaround lens. Yes, I do miss the 50~85, the 35mm once in a while, but overall I like the 17-50 VC better, excluing travel.

For indoor, 17-50 VC definitely beats 17-85 hands down. When I had 17-85, whenever I needed to shoot indoor, I always had to switch to prime, now not necessary anymore with 17-50 VC.

But If it's real dark, you 'll need prime lens like sigma 30mm f1.4, or flash.

If I travel, I'll bring 17-85, but in all the other cases, I'll bring 17-50 VC.

btw, $340 for a 2nd hand 17-85 seems a little bit pricy. A year ago I bought it 2nd hand for only $240. I think nowadays it usually sells under $300 used.