Welcome wandlcorbanaz. You should go to the introduce yourself page and get your initiation
I guess it depends on what you are looking for. The Myerson Hotshot is really only for making clasps and doing small repairs. TCS just came out with its version and they claim you can also do unilaterals and small saddles with theirs (though I guess I'm too old school, I still invest/inject mine). If its just clasps you want then you could also check out the Clasp-Eze from Flexite Company; they are preformed and you just heat them and form them to the tooth you are clasping. However, since you asked about a flexible partial system, none of these are for making flexible rpd, you have to get a real system, then wax/invest/inject (sorry).
Here are some of the more popular systems: 1) Myerson Flexpress. This goes along with the Myerson Duraflex, and you can also program it do other materials. I've not used it, but I hear it is awesome. 2) TCS system. Goes with the TCS, and they have a manual system or pneumatic system (I have the latter and really like it). You can also set the temp to shoot other material. 3) Valplast system. I'm not a big fan of the company, my experience is something (usually material) is always on backorder and their customer service is a joke (or at least it used to be, haven't messed with them in years). There is also the Snowrock system that I've heard good things about but have not personally used, Success which is outdated (especially their material),Flexite which is a good company, but I feel that it is also kind of behind the times. If I had to go with one I'd pick Duraflex or TCS, it kind of comes down to preference. The Duraflex is easier to finish and polish, but it isn't as flexible as the TCS (I've repaired a good number of Duraflex in the past due to breakage on the clasp assembly). Hope this helps!