The Hammershot is my favorite pistol. It beats the Strongarm, at least for me. However, some don't like how it cocks. The Strongarm gets an extra shot since it holds one additional dart, but the Hammershot can be dual wielded...with the Strongarm this is not effectively done, but you can slamfire. It's a tough call and ultimately is based on which style you prefer using. I'm all about Hammershot though! It packs a lot of power, is fast to shoot and easy to load...and you can do so on the fly while firing, with great distance! The trigger pull can be a bit difficult at first but either it gets easier over time or you build up some thumb muscle, and it's great. My son who is 8 has started to use the Hammershot when at first he hated it since it was too difficult for him to pull back all the way. He still needs two hands to do this but he prefers it over the Strongarm since he has issues getting the barrel to pop out of the Strongarm in order to load. Can't really own enough of these guns though. I have 3 and I have a desire to get more, they are just that awesome. It's always a go-to blaster. There are even mods for it to increase the dart amount, if you're into modding.
One thing I really like about the Strongarm though is you can play Russian Roulette. Kick the barrel out of the chamber and load one dart, spin the barrel (which is super fun) and flip it back in, and you're good to go.
This mod has a 3D printed barrel to bring the 5 dart holding capacity up to 7: