I went up there last night to take a look at what was going on and also have a bit of fun. In no particular order, and bear in mind that every evening will be different but a few thoughts based on what I saw on one visit.
Although it is called a red light 'district', all 'advertising' seems restricted to Holbeck Lane / Bridge Road only, I didn't see any girls waiting on Whitehall or Springwell Roads or the smaller cul-de-sacs, even though they appear to be in the permitted zone. I have seen two different maps, that differ slightly in their boundaries. The cul-de-sacs seem to be used more for actually conducting business.
The area is surprisingly small, about 400m max. No activity that I noticed in the area west of the A58.
Many but not all WG's are EE, with a noticeable variety in attractiveness (depends what you are after i suppose).
Rates seem pretty standard between all the girls, 20 for OW and 30 for sex. I didn't ask about cost for 'A' however.
I'd guess up to about 10 - 12 girls at any one time, with numbers seemingly reducing after 12.30 - 1am.
I'm surprised that so many of the girls use the end by Sweet Street and the bridge, as it is not so easy to pull over / turn around there as it is further up.
If you get an extra buzz from deliberately punting street workers, it is probably worth it, provided you don't need to travel too far.
I saw a couple of police vehicles touring round during the time I was there. your are probably more likely to get pulled for a driving offense than anything else. Other drivers stopping or turning suddenly without looking / indicating is something to be aware of, as punters are going to be more interested in the girls, than other road users. It would be embarrassing to have to get recovered from there by the AA after an accident.
The area / girls didn't make me feel unsafe, providing you take sensible precautions about not having cash, phones etc lying around loose in your car.