I want to sell my 70-300 VR Nikkor lens, and get a 150-600mm Sigma Contemporary. That's nearly a $1000 jump ($450 lens to a $1300 lens... Canadian dollars).

I still can't find any half-decent reviews on the lens.

Anyone else eyeing this lens up, or have any recommended reviews?

Go to this site. They keep the review listings up to date. Also check the comments below as a few people (myself included) list the new ones that are found.
http://sigma-rumors.com/2015/03/sigma-150-600mm-f5-6-3-dg-os-hsm-contemporary-reviews-comparisons/

Thanks, much appreciated. Looks like it's still up in the air... Reviews seem to be different from one site to the next. The labs review shows tamron as sharper at 600mm in the center, but another review in another language shows the sigma to be visually muuuuch sharper at 600mm.

Problem with a lot of the reviews is that i think some of them rely on auto focus, and calibration may be needed...minor calibration. I've seen some sample shots that seem off just slightly.

I'm still thinking I'll get the sigma, but I'm waiting on more reviews... The lab review is good, but it goes against some other reviews, and their sample images are terribly done...leading me to wonder if they made some errors.

The other thing is that I wonder if there's a fair bit of sample variation. I'd rather buy right away than get a lens that has been picked through, so to speak.

Ugh, still not sure about the $1350 + tax (Canadian dollars) price tag... but if I don't order it now, I'll have to wait a couple months at least.

Picking up the lens tomorrow

I picked up this lens while I was still on a canon crop sensor.

This lens has been amazing so far. Now that I'm on a nikon full frame (D750), I can't wait to get it back (it's out for the mount switching service).

I think the most deceptive part of the lens is the OS. It seems like its not doing much, but you get sharp images at seriously low shutter speeds at 600mm (even more so on the sport).

Hope you're enjoying the lens!