lol im not really into the leather wallet/case but the Kommadant looks really nice, too expensive for me but i do have to aluminum bumper cases and they do reduce signal but nothing that bothers be atleast. id go for the Kommandant just for the premium feel and amazing look.
For myself personally, having used a wallet case for a good 2 months, it's nothing special. It's convenient in some cases, but when you get coins for change, it kind of sucks. Also, I live in constant fear that I'm going to accidentally drop everything out if it every time I open it. That being said, I'd much rather the wallet over the screw in case. I open my phone up a lot, so yeah. I'm currently using a Neo Hybrid (if you could call it that.. it's fake ) and a tempered glass screen protector. It's awesome Dunno if that helps or not.
I have used the Neo Hybrid on my S4 and its was a GREAT case. It's not aluminum so no signal issues. I will NEVER use a case that flips cloed on the screen. To many issues with scratch/wear on the glass with sand or other particles. Being in your pocket it creates friction on the glass. If it doesn't scratch with sand or dirt, it will likely over time wear away the oleophobic coating on the glass or glass screen protector.