Well, I've mostly been using this type:
From Stirlinghobbyshop. They have a variety of engines and the parts are mostly interchangeable, but I've found problems with these.
I actually like the piston and cylinder in your engine better. The borosilicate glass makes a good seal and doesn't wear out.
The engines I'm using most often (pictured above) have aluminium cylinders with graphite pistons. The cylinders are not polished so the graphite pistons tend to wear out.
The bearings are a little sloppy, but at least it has bearings.
What I guess I like, in spite of them being rather cheaply made is they are available as kits, so all the parts are either bolted together of threaded, so I can do some modifications without having to build the entire engine from scratch.
I'd probably be using Kontax kits. which I believe are very well made precision models, but about triple the price, and I just don't want to pay that much for something I intend to pretty much destroy in the course of my "experimenting" anyway.
I'm actually working on replacing the aluminium cylinders and graphite pistons with glass ones, available pretty cheap. Ones like these are available for about $2 a set.
That is, it would be about $6 for everything in the picture. $2 for one piston and cylinder pair.