It is certainly possible to get a bad engine from anyone. The question is who will stand behind it? DLE has stood up and is being counted now. I fly with two different groups of folks and have noticed how DLE has grown by leaps and bounds. One field used to be Zenoah, DA, 3W, etc. and now DLEs are everywhere and have proven themselves worthy. Support for DLEs is good too (That is you need to buy from a reputable supplier) and no more shaking than any other engine.

Usually if an engine has an excessive amount of vibration there are things that need checking. There are many things that can cause vibration issues. One thing I notice is that folks don't compare them on the same airframe. How do you know you are getting excessive vibrations if you don't compare apples to apples? I had one DLE 30cc that always seemed like it vibrated more than the rest of my engines. Come to find out it was play in the elevator tube assembly. I tightened that up and the whole plane was smooth as can be. Often times vibration is mis-diagnosed because of sound. It my case it created excessive sound that made me think the engine vibrated more than the rest.

There are many culprits to engine vibration. An example would be the run-out on the crankshaft. There could be problems with the crank assembly, the piston, etc. If it were me and I found any of these issues excessive or unacceptable the engine would go back for replacement.

I got rid of all my other engines and run DLE now. If you are frugal you can almost get two DLEs for the price of a single "big name" engine and in my eyes that is the roadmap to getting another plane in the air. The cost is good and the durability is good for my type of flying. Most of the issues I have had have been very small.

It is important to note that there may be a difference if you are flying every day all day long and putting thousands of hours on the engine. The DLE may not have what it takes for that. I cannot vouch for that type of flying, yet for me being a strong weekend warrior I think they are fantastic bang for the buck and I do put them to the test! I have 2 DLE 55s (NIB), 1 DLE 55RA (NIB), 1 DL 50 (durable workhorse), 3 DLE 30s (fantastic engines), and 1 DLE 20 (very powerful little engine). Good luck with whatever you buy.

Side note: I have also heard some news about the AGM engines, yet I did see a video on YouTube that was rather disturbing and would certainly be note worthy. A fellow did a run-out test on a new AGM engine crank and it was horrible! If you start out with an engine with bad run-out you are heading for premature engine failure at some point as that additional strain on the bearings and the entire engine.