Great read so far !
I guess most opinions are focusing on Bally/Williams because they are the most popular machines. DE and Stern Games are not as common, and most DEs are not overpriced (except Guns'N'Roses).
I have played and worked on many DEs, and they don't have the wraps that Bally/williams have. No DEs are "overrated" in my book as there are not too many that are "Highly rated" in the same bracket as TZ, MB etc..
The "High End" Bally/Williams are great games in their own right, but the pricetag can cause then to be "overrated" - No "bang for Buck".
Cactus Canyon, Monster Bash and Medievel Madness are "high End" games that I just walk past on my way to look for an SS or CV. You could almost own and SS and CV for the same price as an MM. MM is nowhere near as good as either !
Fishtales can't be overrated - it is a cheaper family oriented game that is loads of fun and VERY reliable.