I had a G43 when they 1st came out. It was a good size to carry, but I didn't shoot it well. I eventually let it go but always felt it was probably just that individual gun. About a month ago I went into a gun shop with cash in hand. I was interested in one of 4 guns. Sig 365, G43, G43X, and G48. They were out of stock on the Sigs, and I caught the store with a 1 day only special with all 9mm Glocks selling for $400 OTD. The Sig, if one had been in stock was $100 more. I'm still interested in adding one of the Sigs to my safe, but decided at $400 one of the Glocks would come home with me that day.
I handled the G48, but didn't feel it did anything I couldn't do just as well as my G19. The G19 will work with 15, 17, and even 33 round mags plus has a rail for a light which the G48 does not. The G48 is actually bigger than my G19 in every dimension other than thickness and only uses much harder to find 10 round mags I have no problems carrying the G19 in most places. I ruled it out pretty quickly and if I want more ammo capacity the Sig is available with 10,12, and even 15 round mags in a smaller package. I will have one eventually.
The 43X was tempting, but I left with another G43. This one shoots very well for me. The longer grip of both the G48 and G43X were the deal killers for me. Too long for a compact gun. I decided that if I were going small, go small.
Where I think Glock messed up is not making the G43 capable of using the same 10 round magazines as the G43X and G48. I can buy a G26 and use all of the longer mags in it. I think that a standard G43 with the 6 round mags for deep concealed use and the option of using the 10 round mags would have been a better option than the G43X. With, or even without a mag sleeve on the longer magazines you'd have the same thing. S&W and Ruger both offer that option on their compact guns and aftermarket mag sleeves are available if someone worries about such things. I shoot the longer mags in my G19 and G29 without mag sleeves and have never had an issue.