I went on Sunday. A couple of practical tips:
1. If you're going at the weekend, book online and choose your entry time. I checked online on Saturday evening and there were slots available all throughout Sunday. So we decided we didn't need to commit to a particular time, which suited us fine. Got there around lunchtime on Sunday, to discover that they were very nearly sold out and the only entry time still available was 5pm.
2. The "supporter" ticket costs £1.50 extra but for reasons I totally don't understand it counts as a donation which means it qualifies as gift aid. (Not just the £1.50 supplement; the whole lot. That's the bit I don't understand.) So if you're a higher rate tax payer, it actually works out cheaper to buy the more expensive ticket. Bizarre. My wife is a higher rate tax payer so we decided it was her treat for me.
Anyway the exhibition itself is very nicely staged. Lots of space around the huge prints. Plus, although it was supposedly sold out (or at least nearly so for the 5pm slot), it didn't feel incredibly busy. None of this having to peer over other people's shoulders that you unfortunately get at some exhibitions. I think the Hayward are probably doing a canny job of managing the numbers.
If I have one complaint about the staging of the exhibition its that they've gone for a very minimalist look so that the labels giving the titles and descriptions of the works are very unobtrusive - which means, in some cases, hard to find and hard to read! But that's a minor quibble.
I'm up for a discussion of Gursky's work, but I'm not sure whether it would be a good idea in this thread - it would get in the way of practical information for those who might want to visit themselves. Shall we have another thread for that?