[G4 General] hella356:
First off, this is the first time I've not had a rooted phone (upon receiving my old HD2, GS2, & GS4 phones, root and custom ROMs were already available), so comparing the software between the G4 & S4 is sort of apples and oranges at this point. However, I think LG does deserve some criticism for releasing the phone with a locked bootloader. This looks like this will probably change, but is still a BIG negative to me at this time. When you're used to root, it's tough to go stock.

Physical size: while it's fairly compact for a 5.5" device, it's simply larger than what I'd like it to be. This is, of course, largely down to the size of my hands and personal preferences, so is not really a criticism. Had LG released a 5.2" version roughly sized like a G2, but with otherwise identical specs, I'd have definitely tried that over this phone. The variable thickness gives a phone that's very thin at the sides (reminiscent of the S6 Edge, although not as severe), while being beveled in a way that makes it far less stable in my hand than the S4. The G4 is also noticeably heavier, which I don't like.

Rear buttons: I understand LG's thinking, and it's cool seeing manufacturers trying different things, but I am not a fan of the power / volume button arrangement. Having to arch my hand to get my index finger where the buttons are while securing the phone with my other fingers, and then feeling around to press the right button is pretty clunky. The more conventional layout that Samsung uses is more intuitive and simply easier to use with one hand, IMHO. Tap to wake is pretty cool, though.

Softkeys: this is a terrible arrangement to me. Side by side with my S4, when subtracting the screen real estate devoted to the soft keys, the height of the viewable screen is almost identical - the G4 is merely a couple of millimeters taller. In my opinion, this makes the "screen-to-body ratio" figure misleading. With the soft keys hidden, the screen grows, but it then requires an extra gesture to bring them up. This is, to me, a completely unnecessary compromise, especially considering the complete waste of space of the bottom bezel, which is actually larger than the S4's, despite the S4 having a hard button and 2 capacitive buttons. I suppose it makes for a slightly cleaner look, but I value function over form every time, and the LG design is simply less functional than Samsung's.

Screen: I find the screens to be largely comparable. The G4 is brighter, but has less deep blacks. The LG screen is surprisingly reflective, making for difficult viewing in some conditions, but overall there's not much to complain about at all. It's very good.

Camera: the LG is the easy winner here, but I'm not a big photography guy and the two year old S4 still does quite well.

Performance: the G4 is quicker and snappier in general. The S4 is still quite capable, but the more current specs of the LG make it the better performer overall.

Headphone jack: I prefer the jack on top. While holding the phone in my left hand, the phone ends up resting somewhat on the headphone connector, which is physically uncomfortable, makes the phone harder to hold, and makes me worry about damaging the jack over time.

Speaker: this isn't of huge importance to me, but there's no doubt the G4 speaker is significantly louder than the S4. It's also got a bit more heft to the sound, although it's slightly more shrill sounding than the S4.

Most of my criticisms of the G4 are down to my personal preferences, so - for example - I won't say the phone is too big, it's just too big for me, so that's not to knock the device for everyone. I'm going to continue with it for now to see if I adapt to the G4, but in all likelihood I'll be returning it. The free 128GB SD + 32GB SD + extra battery + external charger are really great deals, but ultimately I don't think the tradeoffs of the phone will make it worth it to me.