Well, let's see I started collecting Traveller back in '77 started JTAS with issue #4, bought the '81 versions, and every supplement and adventure and double adventure book and every traveller themed game GDW came out with , bought every version since EXCEPT the Gurps stuff and perhaps the translight, even bought the T20 book and some of the other guy's stuff that's in the stores now.
Played some GURPS D+D stuff HATED the point buy character generation system, it became an excercize in min-max. Saw GURPS Traveller had that as well and the ONLY gurps title I've bought is the interstellar wars book, and that's just for a sourse book.
I really get into the gearhead stuff, designing ships and analyzing their economic performance. At one point I created a spreadsheet that would accept a full sector + 6 parsec expansion into the next sectors over. The sheet would take the economic extensions and the pocket empires stuff to be able to put a number to the weekly tons of trade goods available at a given system. The sheet would calculate the performance of the ship, and all expenses and automate all the trading that the ship would do, and take care of all the bookeeping. It'd show you all the systems within your ship's jump range and give you an estimate of your profit/loss at that system. You could set a flag to use CT or MT or TNE, or T4 design ships.
So for me the more gearheady the ship design rules , the closer to real world I could make them the better I liked it. But it's all traveller to me. I hated what the rebellion and the virus did to the imperium, so IMTU that is just totally ignored. Dullinor was a good little arch duke and never did anything whatsoever untoward and lived out his life in peace and happiness, as did the trillions of Imperial citizens.
I use the TNE and T4 FF+S in parallel, the TNE has better explainations, the T4 has better organization with (nearly) all the charts in one section. Though the charts need ref to page numbers where the controlling explaination lies.
Otherwize I mix and match whatever sections of rules I like from which ever edition of the rules.