I think the major error in UFTree 3.0 is that if you have a citation in your (bio?) text and you print a Family Journal, it won't print any of the text after the citation but instead just leaves blank lines.
Since it doesn't matter where you put UFTree, as long as you don't move it after you have connected to the project files, you can install 3.0 anywhere you like on your computer. Then use the internal pointer to your databases. Then you can use all of the useful parts of 3.0 and merrily go on adding data and text. Then, if you want to print a journal where the text happens to include a citation in the body of that text, then go back and use the older version of UFTree to print the family journal report. There may be other problems but I have not run into them.
There are some 3.0 improvements that speed up entering identical data into several records. In 3.0 it is possible to backup the dictionary, task lists, sticky note, revent libraries, right mouse settings, and user preferences. 3.0 has improved Evidence templates which you should download the latest of, and a batch of English events that should also be downloaded for the latest. Footnoting now has three choices, long, short, and ibid. 3.0 allows changes in the width of rings/arcs in fan charts. All in all, generally, 3.0 feels better than some earlier versions.
I'm pleased I upgraded even though I haven't had a lot of time to enter new data. It rather depends on where you are coming from.
If you are using 2.0 or so, you can do much better with 3.0. If you have 2.8 or 2.9, then you might want the 3.0 improvements now or prefer to wait a bit.
We might get lucky and discover a 3.1 that fix some nuisances, or patches for the problems. After all, 3.0 came out last June. Based on past history, something should happen in the not to distant future. Don't quote me on that. I don't know a thing, just supposin'.