Had both a new 2011 50 hp 4-stroke on my previous boat and recently bought a brand new 40 hp Mercury 4-stroke for a lighter boat I completely rebuilt.
Very reliable, quite and smooth. I really like them + you can find service shops almost everywhere!
Recommend Power tilt and trim.
If buying new, It's well worth getting Mercury's extended factory warranty giving you 5 years backup.
The cost is very reasonable.
Retired and loving it!