well, as far as looks go that is entirely personal. I have a 2012 and have tour tech crash bars
on it. one of the reasons is the way they look. I personally don't like the bars to be obvious though some do. and I like the parts they cover.
any rate all of them that I know can get in the way of maintenance a bit. basically BMW brand and touratech can get the spark plugs out but not get the valve covers off. I can't say for others.
though it is not really a problem for mine. i only need the valve covers off rarely and not typically in the field. I do also have valve cover guards which I can take off without taking off the engine guards. also true for the BMW ones.
the only warning I would give is about how strong they are. some people tend to think that the strongest are the best. this is not nessacarly so. too week would be a problem obviously, or at least pointless. but to strong and along with mounting against the crank case and the next thing you know you can have a problem. you want them to bend when you go down hard. absorb energy, but not to much. to be clear I have replaced the right side twice and the left side once.
one on the right I was moving about thirty mph on a gravel road. 30mph and about 700lbs of bike and 200lbs of me and real quick the energy is through the roof. it bent back but not into the head. so bike saved and replace the side so it is ready again. At first I was a bit bummed until I worked out the force involved. I was not surprised that it bent and I was glad.
I tend to be aggressive at times and that has led to having to replace the sides periodically. one of the other times was on a pass in colorado and I managed to slip out landing on the left or rather the massive bolder stopped the bike from about 20 to nothing in no distance. still didn't get into the head.
at the same time many slower drops have ground a couple of marks into them but they have no deformations.
any rate I hope that is some food for thought.
while I am sometimes aggressive (I am getting less) I am not that good so I have tested the bars quite a lot. here is a video of mine showing how good a field tester I can some times be. Gateway BMW GS Challange