I am blessed and started to collect and use AP stuff in 2016 or so.   Anyways, I now have both a 1600 and an 1100.   The 1100 is my new portable setup, which I have yet to take portable....uggg.  The 1600 is the back yard observatory.  I want to get the encoders for the most needy first.   My guess is that this is the portable mount.   The observatory mount is wonderful.  I have not had to tweak alignment since installation.  Guiding, probably because of the modeling, has actually gotten better best I can tell.   Maybe it is my more precise balancing or probably most likely my expanded knowledge base on how to use the thing.

The 1100 is almost as good.  I think the almost is probably due to the exposed position it is in.  There have been nights where I just can't belive the accuracy even on that thing and they happen to coincide with, well, wind opr better stated lack thereof.

Anyways, which would you upgrade first?  I know the why will come with it.   I want to get on the correct list.  I don't want to do both at one time.