It's funny you mentioned Pearl Hotel. Pearl Hotel is the first so called 5 star hotel in Phuket but of course this was about 30 or 40 odd years ago way way before tourism was even a thought and tin mining was the way to go. The ground floor coffee shop was the local tin tycoon's hang out. History lesson apart, from what I hear the massage joint has been there since the hotel opened. I think it might be a good laugh to go up there for a look but the place probably hasn't been refurbished since it opened and the girls working there have probably been there since the hotel opened too.
As for the Phun Phon area of town, I'd put my bets here instead of Pearl Hotel. Le Residence and Katherine are both good but I think Katherine may be a better idea if you don't speak Thai as they speak some English and they even have a pretty good website in English. Besides these two places, there's at least another dozen or more other massage joints in that area. Enjoy!