I tow a trailer behind my 2017 Street Glide.  You need to pay attention to getting the weight over the draw bar near the right amount or the bike steers like a pig but get it right and the only time I know the trailer is there is when I'm braking hard in a hurry.  It still stops straight but it takes longer... sort of like having a fat arse pillion on the back.

If it doesn't fit on the bike, you don't need it.

Just got back from a 6,200 km 12 day trip, the stage 2 M8 Roadking pulled the trailer quite well.

Lots of benefits with a trailer,

 I have a couple of trailer oufits, I tow one behind my BMW, and also behind an old Goldwing,  but there are some things you have to be mindful of,

1   Make sure you have more weight in front of the trailers axle than there is behind it, this is really important, happened to me, thought I'd blown a trailer tyre, you wouldn't
     believe how much the trailer whipped from side to side, the bike also, scary as,
2   Fuel comsumtption suffers a lot, my bike without trailer 300k's, with trailer and I'm looking for fuel at a little over 200k's
3   Stopping distance is increased, you have to plan well ahead, in an emergency stop situation you are fucked,
4   My BMW has a really high first gear, a lot of revs and clutch slipping to get going, again planning is the key, do not stop on a steep incline, you may never take off,
5   Got to be careful going around bends in the road at speed, the trailer will tend to try and push you,
6   A bike plus a trailer is a long outfit, plan for parking, it's not easy to push a bike with trailer backwards,

So if you are careful and know the limitations, trailers are a lot of fun,

 my BMW outfit, Classic Trailer, this trailers axle is set well back, I've never had a handling problem with this trailer,

I've got this old Goldwing which came with a matching trailer, nice outfit, but note the trailers axle is in the centre of the box section,  if you have too much weight behind the axle believe me you are in for a ride, once you get the wobble the trailer will throw the bike from one side of the road to the other, it only happens once,

I got my tow bar for an 08 custom softail from classic motorcycle industries in yandina.  They make em on order and post for 50 bucks. There towbars are $450.00 nice unit. Looks good. I like the fact that the lower bars on the towbar are positioned just above the rear axle each side of bike which means rear wheel can be pulled of for tyre change without removing towbar.

Weasel, towing a trailer is not a problem if you plan a bit further ahead as riding without a trailer.
And I agree with some, motorcycles are not made to tow trailers, but can help with marriage harmony. I only use my trailer when She Who Must Obeyed is along for a trip, for the boys trips I have my trusty swag.
I have towed as far north as Cook town and south around the coast via Moto GP to Port Fairey near SA southern border.
The longest trip was a month and 7500 kls.
The old ultra I was towing with did the job very well, like what others said they use more fuel. I installed a larger fuel tank (22 litre Bagger Nation Tank) as the 2007 CVO only had the 18.9 litre tank.
My trailer is an alloy Elite with a Austrack tent top. As others said wives carry lots and LOTS of stuff and the trailer and bike get well loaded. We have a 50 litre fridge, toilet, solar power, 35ah batteries, full annex, 10 lit water, stove, chairs and heaps of other stuff. The trailer can get up to 320 kgs. but I try and limit it to 280 kgs. Usually by removing one battery, toilet and a couple of other heavy items. Just because you can fit lots of shit in doesn't mean you should! I have a couple of friends who don't worry about weight and have around 350kgs. One of these blokes blew the shocks on the softail, then changed the suspension to a SAS air ride and broke the knuckles off them, he rides hard, no pillion as his cook rides her own bike.
The CVO didn't have ABS so I doubled the size of the brakes on the trailer, extra trailer brakes means more rear bike brakes and less front bike brake, the opposite of braking normally. In extreme braking the trailer brakes loads the towbar up and lightens the front wheel making a front wheel lock-up possible, don't take this out of context I am saying extreme cases. with ABS it's not a problem. The Elite trailers are built with single piston calipers and I installed double piston calipers.
I have recently retired the ultra with 97,000 kls. and have a Victory Cross Country to tow with.
I have never had a problem or an incident while towing but I do plan plan plan. I have done 145KPH with trailer on but not two up, it remained stable. Bikes move around more with trailers but you get used to that over the miles. There are 5 in my ride group with trailers and none of them have had any majors with towing. Friends have been right round the big block and the only thing one had to do was change the trailer bearings, he had the small 8" wheels, he now has the bigger wheels. He has a Road King and another a Roadie, another a Fattie, a Street Glide, a BMW GTL 6 cylinder. Three of these have been around the block or very near to all the way round.
Like always don't do stupid things and avoid the idiots and all should be ok.
I don't know how long I will keep trailering as I am nearing retirement age but I think I should go a few more years.
Good luck with your choice and happy travels.

Thought ide add this. 

Gotta be english, no ice and warm.