I like both SSMS and ADS. I have both installed on any development machine I have access to. (I won't put it on a server, as that's not my business.) Personally, I prefer ADS to SSMS. I love the SQL development in ADS to SSMS. We don't have Redgate's SQL Prompt here and I very strongly doubt that management will pay for it, even for the DBAs. Much to the loss of the DBAs. Anyway ADS, at least for me, fits the SQL writing slot.
The one area that SSMS is far superior to ADS, in my experience, is being able to see what's in a database, dependencies for a table or view, etc. Many is the time I've tried opening ADS to open a database and look at the columns of a table, but ADS is, for whatever reason, much slower than SSMS. For that reason alone I won't give up SSMS.
Kindest Regards, Rod Connect with me on LinkedIn.