As I former JW I will speak only for myself. After leaving the JW’s, it was very difficult to consider any other religion. It was so drilled into my head that the JW’s were the only true religion, I felt that if they were wrong, nobody was right.
After a time, I learned that everything I was taught was wrong (most specifically the Trinity) so I would never have been drawn to another religion that believed that Jesus was not divine.
In my experience with counter cult JW ministries, most who leave the organization become born again Christians - so on fire for Jesus.
Also, although the JW’s & Mormons are similar in that both don’t believe in the trinity, JW’s have all those other rules (no holidays, no flag, no voting, no military, no blood) which is not compatable with the Mormon Church.
JW’s for years did not believe in higher education so as a group, I believe they are less financially well off as Mormons. I personally never knew an even slightly wealthy JW… so never having any money is sort of depressing - especially when you tell yourself that soon you will have your pick of the houses when Armageddon comes and Jehovah destroys all the wicked (everyone who isn’t a faithful JW). But Armageddon doesn’t come… so that is depressing as well. And the no holiday thing is depressing also. Yes, I agree… in general, being a JW does not make for a happy life.
I never heard of a JW who was a former Mormon. Never. The converts were almost always former Catholics. We would look for Catholics because most didn’t know the Bible well enough to fend off our attacks.