Just for the record - asking what are the better brands (or similar) is very much a personal point of view in most cases. What one person considers good, others may not and so on. What I am saying is you are most likely not going to get a definitive answer as there really is no definitive answer.
For example, Rico says that you can't go past atlas engines in any scale for anything - I model N Scale and I wouldn't touch an atlas engine but prefer Kato engines. So, which one of us is right? Rico or me? When it comes down to it - we are both right depending on our own experiences.
When it comes to buying engines (as opposed to rollingstock) you have to consider a few things:
1. Do you want DC or DCC or DCC with Sound?
2. What can I afford to spend on an engine?
3. What is most important to me - Looks or Reliability and Performance?
4, What makes are readily available and easily obtainable?
5. Which brands/makes have a poor or questionable reputation?
6. What is my end goal with my layout?
7. Do I want Steam or Diesel or Both?
Once you have answered those questions, then you can look at what Engines to buy and ask if anyone has had any issues with a particular engine, make and model. Sometimes it comes to down to not only the Make or Brand, but the Model and Year a particular engine was made.
All I can tell you for certain though is to buy NEW and not used, or if you do buy used, buy from someone you personally know. There are a lot of sharks in the world, especially at Train Shows just trying to rid themselves of their junk
