MicrostockGroup

I moved some of my best sellers to Photo+ as soon as possible as an experiment, and didn't notice any negative effect, just a positive effect on earning.

The same is true at Fotolia, where I put all my files at maximum allowed price.

So my opinion is that buyers are not so price-sensitive (within limits)

I agree.  P+ has given a real boost to my earnings without appearing to affect volume of sales negatively. 

My experience with P+ has been positive too - it is hard to be really certain about this as so many other site ups and downs and best match shifts muddy the statistical waters.

The reason I think it works so well is that all the exclusive content on the site is already at that price, so from a buyer's perspective it's more like removing a discount rather than increasing the price. The Vetta/Agency uplift they notice as it's so enormous, but IMO not the P+

But of course we don't know about the sales we didn't make, and there was some worry that over time best match position might decline (as some had reported it did with Exclusive+, but that was quite a large boost in price).

It's worked for me.  We'll see what happens once those same files join the PP.