Some thoughts from a bloke who has owned both for a few years.
SPOILER: I still have the 87 clone.
When I first bought my 1887 IAC chinesium Lever gun, it was a bit of a let down. I had a lot of remington 12g SG rounds that I’d bought in bulk for my under & over and they didn’t work well in my flash new rapid fire death machine. They hardly worked, in fact. This point was made worse by the fact that my shooting buddy had an 1887 too and it cycled them just fine 
I guessed Id bought a dud.
But I hadn’t. It was much the case that chinese remakes were hit and miss with all different kinds of ammo. In the end, Federal shells with very short brass case heads were the bees knees. No more stove piping, no failure to lift one into the chamber.
This was in stark contrast to the Adler A110 Lever gun from the kebab shop. Much like a kebab, you fill it with anything and as long as it’s cheap it works. Well okay, not true for kebabs. But the Adler would convert any cartridges into lifeless hulls at a rapid rate. Low brass, high brass, paper hull, full brass hull, it would shoot anything from salt and steel shot to slugs and did not hang up once. I shot boxes of clays with it. It was much lighter, take down was considerably easier; the 1887 main spring was a bastard to reseat, and one of the Adler sear springs is like that too, but on paper the 1887 takes a lot of work and memory to reassemble.
Shooting the adler is easy. It has a nice rubber butt pad that absorbs some of the kick. At 20", the All Weather model is a bit of a mule by the time 5 or 6 rounds have been shot. The 1887, with its solid plate would sting you, but with a pad on it, its magic to shoot. Im as tall as Hickok45, so I often have a slip on recoil pad fitted to get me closer to that ideal 15" L.O.P. at the expense of sanitary pad jokes from my “friends”. Haha. They say Dick Cheney used a pad too.
I imagine loading an 870 Remington Pump action is similar to the Adler with its lightly sprung loading gate under the reciever letting your thumb push the cartridges into the tube. The 87 requires significantly more fidling as the action needs to be open and its is fed through the top, where it ejects from. It requires some dexterity to drop shells in straight and using your index finger to push it all the way into the tube magazine. Its kind of like ummm…well…use your imagination. Small hands would strive. That said, with practice, lots and lots of practice, you can quickly load two shells into the gun and fire them off almost as fast as an under and over. This is achieved by dropping two shells straight down into the open action; one sits in the ready to lift position (not in the tube) and the other above it in the raised lift itself. On closing the action, the chamber is loaded and ready to fire with one more round wating for a quick cycle to pick it up. A five round ‘post adler’ legal 1887 can hide another round in the lift, and one up the spout for total of seven making it a legal Category WMD. Mine still has the seven round tube, but modified with some trusty dowel and a few rums to hold a less lethal five rounds of lethal baby killing warheads.
I ended up sending my 1887 off to a very competent gunsmith in SA who sent it back to me with a whole lot of filing and polishing action slicking completed. Its cycles like buttery greased butter factory grease guns. Its a pleasure to own.
The Adler I enjoyed for some time, but quickly tired of it. The alleged ‘All Weather’ finish was shithouse. One outing in a rainy wet season and the reciver was irreversibly pattina’d by my own sweat and rain. It was well tarnished and looked like crap. No biggy. Then there was the ‘iron’ sights. They were off centre, and the rear ramp was bent downward, which was annoying. But the feel of shooting the Adler, it was not a pleasure. It wasn’t enjoyable though it did take pigs and clays. The trigger is shocking, and I fitted an I.C.E. slicking kit but it wasn’t able to change what was missing: enjoyment!
Maybe a heavier Walnut stocked Adler version would have been a better choice, but Ive kept the 1887 clone instead.
