I'll borrow anything from it that fits my house rules but I will not use T5 as a core rules set.
That's my preference as well. Of course, my goal is to have T5 replace as many elements of my house rule system as possible. I want each module in T5's core rules to be an organic or evolutionary step beyond what came before. The better T5 develops, the more of CT I can finally leave behind.
My house rules were, more or less, The Traveller Book (with a couple of annotations), High Guard, Citizens of the Imperium, MTs task system, design elements from MegaTraveller back-ported to CT, and the equipment and vehicle lists in MT's Imperial Encyclopedia. And some other things I'm sure I'm not remembering from the huge pile of CT material. Plus all OTU setting material.
First, T5 replaced "Book 1" and CotI. Then, weapons, armor, vehicles, and most of Book 8. Then "Book 2" (and then some) plus MT extras, with starship design from TL 7 to TL 22 (with some elements extending that to TL 32). Then most of Books 3 and 7, and parts of Book 6. And some things that no version of Traveller had.
With each subsequent draft document I could replace another element of my house rules with something better. Weapons, armor, vehicles, and starships are compatible with CT, and therefore MGT with a minor conversion.
I still have a couple "house rule" elements waiting to be replaced (for example, an equipment list). But there's not much left. Although, the drafts are still under revision.