If you want a watch to look like a watch then round is pretty well the norm. If you have a smart watch what shape should it be!  doesn't matter as long as its functional and not to over the top.

How it looks is entirely subjective so if you are buying on looks alone then take your pick there are a lot on the market.

If you are looking for functionality then these two watches are different given one can be used as a stand alone phone.

Yes the Moto 360 looks like a conventional watch as its round and some would say its nice looking (so is the LG watch) but being round it has its draw backs at the moment as most apps are set up for square/rectangular screens.

Battery life with the 360 with a screen always on will always be an issue but its inconvenient to have to lift arm a certain way to switch watch on in the case of Samsung.

The firmware android/tizen isn't an issue really but would depend on what you want to do, if its notifications then all is fine with either, I only use my watch for notifications, time etc and the phone if I need to ring but do find the ability to use watch in car as phone very useful (mine doesn't have a sim)

Once again it gets down to what suits the individual not what others think is best