If on TBN you start to get confused by rich a variety of opinions, try to focus on the circumstances and experience of each poster who voices the opinions. As to the question of HST vs. gear, members fall into four categories:
1. People, like me, who bought HST from the get-go and who hence have no actual experience using gear tractors. You may want to discount our credibility for that reason. Fact is, the overwhelming majority of people who buy CUT size tractors these days opt for HST. So, this is a large group here.
2. People who have lots of experience, perhaps a lifetime's experience, using gear tractors but who have never owned and used an HST tractor for an extended period.
3. People who have many years experience using gear tractors who have switched to HST. This is perhaps the group with the best perspective. There are many, many such members here, but not a lot of them have responded in this thread. I have tried accurately (and without any axe to grind) to summarize the uniformly positive nature of their comments.
4. People who have many years experience using HST and who then switch to gear. I don't recall any such person--unless they were upgrading to utility size tractor where HST is not available.
5030 says "it depends". He has a gazillion tractors and I wouldn't presume to interpret what he meant by that. But others have stated, and it seems reasonable to me, that gear tractors work just fine for traditional dirt-engaging field work (farming long rows). Also, if you go up higher than CUT size, HST will not (yet) be available. Some have speculated that this is because HST transmissions may heat up too much with a heavy tractor dragging a very heavy load through the ground. Don't know myself.
That about exhausts the info and viewpoints I have. To try to fairly summarize, if the type of tractoring you do will involve lots of start-stops, backing up and changes of direction, then HST will be the simpler and easier to use transmission, will be less tiring for the operator, and will increase the speed and efficiency with which you can complete tasks. Necessary?....no. Cost more? ... a little.