So, look at what you're doing. Just like the rest of us, you started off with something small, affordable, etc.. now it's time to upgrade and you're getting into 5th wheels. Nice upgrade! How many times do you want to upgrade the hitch?? Its like having 4 wheel drive (depending where you live) it's a somewhat expensive option that you dont use much, BUT the one time you REALLY need it, it was there and worth every dime. Hitch in a standard bed is the same way. How many times will you really need a slider? Kinda depends on how much cutback there is on the front corners of the front cap of the trailer. The one time you need the slider hitch, and you didnt have it, and you made a mistake and now the back window of your truck is blown out and the cab of the truck is crunched. Pay a little now, in a good hitch, instead of a lot later, in damage repair bills.
This is MY opinion, I've had a rail system style 5th wheel hitch before, never had a slider because I've always had long box trucks. Rail system worked just fine for our first 5th wheel, but the whole thing seemed too noisy, too much play, etc... I have a B&W Companion that uses the Turnover under bed frame mounted system. That hitch in mounted in my bed SOLID. Its quiet, doesnt flex like the other one did, not all loosey goosey like the other style, and BIG difference in how the trailer pulls going down the road. I installed both of my hitches and I'd go with the B&W hands down. I've also installed 3 B&W sliders, 2 were using the Turnover and one was a puck system, so I dont know if that really counts. Lol!
The B&W is a manual slider hitch. If you were looking at auto slider hitches, either a Demco or a Pullrite.
My uncle has a Pullrite. His is a rail system mounted hitch. Nice hitch but coupling and uncoupling can/will be a pain. I cant really speak of how it pulls his trailer, but he says it's ok. He gets a little bit of noise, and more chucking compared to how mine pulls.
Getting into how the ride quality is as far as bounce and chucking, etc., that's a whole different story. Now you're getting into different pin boxes on your 5th wheel, etc...
I will say trailers AND trucks will all pull different.
Example, I have a 15 Silverado 3500 crew long bed dually. I pull a 44' Northpoint 375. I have a B&W Companion/Turnover and a Moryde pinbox on my trailer. That combo is a really good setup.
My buddy had a 16 Silverado 2500 crew standard bed. He pulls a Jayco 29.5 with a Moryde pinbox and has a B&W slider/Turnover. His trailer pulls much better with the Moryde pinbox and he and the Mrs say it pulls pretty well, until..... He had an unfortunate accident with his truck, moron t-boned him, driver side. We had 2 trips left for the season. One of the trips his Mrs and child rode with us in our truck, pulling our trailer and she said she was amazed at how smooth ours is compared to theirs. The last trip I towed their trailer with my truck and she was with us again and said how much better my truck pulls their trailer. She also noticed that the ride is even better in my truck pulling my trailer compared to my truck pulling their smaller trailer.
Now I've made it clear as mud for you and you're all confused, lol!,. In short, do yourself a HUGE favor and go with a slider, you may not need it all the time but when you do, it's there. As far as auto vs manual, that's up to you to weigh out the pros and cons of opinions out there and what you find doing some homework. When it comes to the hitch, dont go cheap.
2017 North Point 375BHFS
2015 Silverado 3500HD Crew Dually Dmax 4x4