I've carried the original Shield for years. This Hellcat is my carry gun now. Attached the Hex Wasp easily and it was cowitnessed right on.
Wasp red dot is easy to use, MOA size is good for close shots, and small enough for longer ranges. Auto dimming appears to work fairly well, but I'd prefer to be able to manually dim as well.
Got the 15 rd mag. It makes the grip length near a full size feel, hand grip stippling is very nice and makes grip and control easy for a micro. Even though the grip width measures the same as as the Shield within .05 in, the Hellcat feels much larger due to shape and stippling I think.
15 rd mag is tight to load all 15 into, but it works well. Mag release is perfect size and functions well w/o fumbling. Rapid mag swaps are easy.
I appendix carry IWB and the 15 rd mag extra length is no problem.
My local range is max of 12.5 yds, and controlled shots were easily placed. It is a bit snappy, as micros are, but it is easier to shoot than my Shield, which is definitely more snappy and harder to get back on target than the Hellcat.
I considered the Sig 365 and the Hellcat for this purchase as both offered cowitnessed red dots as a package. I shot both and saw little difference, and actually like the Hellcat rear U shaped iron sight. The Shield Plus is a great gun as well, but it has no cowitnessed red dot package offered right now.
Some reviews of the Hellcat mentioned some shooters tight grip activating the slide catch inadvertently and accidentally locking the slide back while shooting. Not a good thing in a gunfight. I had zero problem with that using a normal 2 handed grip. I have medium to large hands.
If you're used to thumbing down on the slide release, you'll find it tight for a while. Mine loosened up after about 100 rds. With a mag in, slingshot works fine and slide is easy to grip whether you use 2 fingers, or put your whole paw over the top. Also, the Wasp was aggressively tested as a means to help rack/release the slide. The Wasp is aluminum and very tough so you can easily and safely use it for this. See YouTube reviews for more info if you want.
Another issue I read about was the safety trigger locking up if lateral pressure was applied. I found that shooting this gun with my 2 handed grip with trigger finger indexed, then moved to trigger for firing, it always laid right on the safety portion of trigger first and activated the trigger correctly 100% of the time. Lateral pressure on any safety trigger can lock it up, they're designed that way. Correct technique and training will yield correct results. I found the Hellcat trigger worked perfectly.
Overall, a great package with the 15 rd mag and Wasp red dot.