I have a Spikes Tactical 16" 5.56 that I've had for over 17 years with no complaints. Have built a 300BLK with their upper and lower receivers that's taken many pigs and no complaints.
I like the 300Blk, killed quite a few pigs with the round. I haven't owned or shot a 5" but I bet it would still hit paper at 50. Look up some ballistics at 50. If going for a subsonic only setup may wanna go with a 5" twist bbl.
Less milling on slide, just white dot front sight not NS, plastic optics cover instead of metal, just one pin set for optic, one SS flush fit mag, no nylon pistol bag, whit box instead of black.
I understand what your saying. No pistol fits everyone the same. Just like Glocks, some don't like the grip hump either, some don't mind. I like the Echelon hump, it kinda feels like a Glock hump that I'm so use to.
Looks like the same slide serrations as the XD Mod.4.
I don't see this new SS magazine on their site. Hopefully they offer it and costs less than the blackened std Echelon mags.