Habanos for sure. That's always been source #1 in Panama (at least post-Veneto). Never tried La Bocaterena, it's lower end though you never know what you might find.
Aside from Habanos, I met chicas from Alejandros, Le Palace, Golden Fingers/Golden Time and the massage ads on Wanuncios. Alejandros is hit and miss but always worth a visit for recon, I have found some great gems there in the past (though lately it's been more miss). Le Palace has the highest quality in town, but also the most expensive. It will run you near $400 to pull a chica from Le Palace, though you can always get phone numbers to meet outside the club when they are not working. The Wanuncios ads are also worth a look, most of the quality is average but there are usually a few good looking massage girls and the occasional hottie. One of them is now a regular I have over for a few hours when I'm in town - drinks at the bar, then a movie and spectacular mileage. Have another possible regular there too, will find out when I'm in town next - soon. The casino bar at JW Marriott is also a good source, though the going price is closer to 200 compared with 120-150 at Habanos.
The beauty of Panama is the scene is mostly freelancers, from Colombia and other Latin countries. So it's fairly easy to arrange dates, dinner, overnights, whatever you want as long as the girl is up for it.