Theres good engines, theres bad engines, everyone has there own opinion about engines.
Dont forget that some engines perform better when they are on an angle too, and some have fuel injection, some dont, fuel injection is a waste of hard earned money if you are just sport flying.
Here is my 2 cents worth though,

Pros.....................Cons
L.A- reliable not as durable
M.D.S- inexpensive dont run half the time
FX seriese- more power drain your tanks

As you can see engine have there goods and thee bads, just like anythnig else that is on the market.

Jim