Check the price of cylinder head covers. They used to be pretty cheap...and the guards are pretty expensive. I did without for years. I scractched on side in a drop once and got a new cover for about $75.
If you drop the biike on the guards, they look crappy and you want to buy new ones. A pair of those (you can't buy one) cost more than a cylinder head...or used to.
That said, I bought the Illiums for my '17. Had a Wunderlich on my '05. The Wunderlich never fit right but the Illium works great, looks good to me and if you drop the bike, you can spray paint the bar on the bike and make it look near new again. Put a piece of cardboard behind to catch over-spray.
The chief consideration for me was "can I change oil and check valves without removing this thing?". The Illium is not only the least expensive, but, I think the easiest to install and the nicest looking one that doesn't require removals of any kind to do normal maintenance. You really need both front and rear bars to protect the bike but the front will insure that you can keep going and not puncture the valve cover and lose oil.
I've done enough back-roading in the middle of nowhere on mine (yes, you can) to appreciate that front bar's protection...and it makes my bike look cool too.
Pick your poison...or go without. All are valid decisions. Depends on how, where and how well you ride. Experienced riders who are not into pushing their bikes anymore are probably not going to need any protection. Adventurers and enthusiastic riders who go where they shouldn't and do things that challenge them probably should have at least a front bar. A low-side fall, for instance, can put a hole in the cover if the bikes slides on it long enough. Front will prevent that but other bits will be skinned up.
If you want to protect all the bits from scrapes, you need both front and rear. For RTLs, I like Illium for front and rear...I like my silver front. Would get a flat black rear if I ever get one..my bike is black-ish. I don't like the rear one to show. Silver front blend with color of cylinders and works for me.
...and Illium also for their bar-baks. They move the bar only a little back and a little more up, but for me, it makes a massive difference. I use an Aeroflow Tall screen. Leaning forward into the wind is not a thing on my bike, so having the bars higher and back a little really makes it nicer.
I have no affiliation, just like their straight-forward designs and products.