The majority of my punts are with EE girls and the vast majority of those punts were positive. I have stopped TOFTT with Romanians as I've had the most negatives with them and generally avoid them now unless they are well reviewed or come recommended. Most Hungarians I've seen offer a good and reliable service. Polish girls are my favourites at the moment, very good looking and also offer a good and reliable service. Always confirm services when you book and reconfirm them before handing over any money to the girl. I've walked away several times when suddenly what was on offer becomes extra or a service they don't offer.
So depending on your feeling I see no harm in trying a new girl if you've checked her profile and can't see the telltale signs of a bad punt, phoned her, confirmed services and got a general vibe from the call. After all, a large part of the excitement of a punt is trying something new and not knowing what to expect and when the girl is good you leave on a high knowing you took that punt.
Your regular could be a back up plan if seeing the new girl doesn't work out for whatever reason.