I always treat these with caution. You knock the door and of course the door opens by the invisible woman
step inside, have a look, if you don't like what you see walk back out onto plan B. In my case I have mostly positive experiences with these lower end budget girls. They have been damn good down here in Cardiff.
The big problem is that you never get to know the girls name, and they move on after a week, or two at most. So no point in reviewing. A gaff that had an excellent girl one week may have a dud the next.
It is very much pot luck, but by doing a bit of research you can significantly improve your odds. I tend to go for those claiming to be independent, and avoid the agencies with large numbers of ads. Often these agencies post multiple ads, some claiming to be independent. It pays to compare phone numbers and the wording in ads, and what postcode they quote in their texts, to look for things in common. I just automatically assume that the photos in the ads are fake, bait to reel you in, but occasionally some of these setups will offer to WhatsApp you genuine photos / videos. By doing the research, and working out the gaffs to avoid, I have scored quite a high success rate with Chinese SPs of late, some really good punts at very cheap rates.
Even if the VS ad doesn't state any extras charges, just everything ticked green, and the text detailing services doesn't mention extras, in my experience, Chinese SPs invariably want extra for things like owo, cim and fk. However, when you get there, the girls rarely ask upfront if you want extras. They ask how long you want to stay, and that is it. Asking and paying for extras up front seems to get you a much better service. Paying just an extra £10 or £20 up front for owo or fk for example can get you a much better experience. I suspect you are seen as a better customer because the girls get to keep all the extras money, unlike the hourly cost which has a hefty boss fee deducted.