I got T20. I liked it for what I got it for. Actually I liked in general but possibly thats helped because I got it for a reason. I recognise that there are some issues with its layout if you come to it cold, but then that could be said of any number of supplements/games based on the D20 system and license which cannot be blamed upon the makers of anyone having to operate there.
It did do exactly what it said on the tin. It took Traveller to the D20 market demographic and it succeeded (IMO YMMV AOTLA). Thats the context the T20 system should be judged by, both then and now. The corporate issues are linked and may affect decisions but they should seen separately from the system.
Given that there were reprints of classic Traveller around this wasn't a product that could really say it was trying to be 'Traveller'. It should be regarded as a specialist.
So what was it for...well I think I used it how it was best used. I had a group, two of us wanted to do Traveller, but two guys were only familiar with D20 and wanted to stick to that system. T20 was perfect for that situation. It was cross-platform enough that I used Spycraft and SG1 material from the D20 side, and material from GURPS Traveller and a couple of LBB bits as well - not to mention the Counterstrike map
Was it ideal. No, it was not perfect for Traveller. Traveller comes with a set of concepts that vary from common metrics present in level/class based RPG systems. T20 did a good job of shifting the emphasis the right way, but its did not completely replicate a dedicated Traveller system. When D20 'ruled' (for want of a better phrase), it was useful. Now? Hmmmm.
If someone came and asked 'should I use T20 now?', what would my reply be? I think I'd say on the plus side - 'If you have players who know D20 well, and are only really comfortable with d20, you have a defined story arc and can get ALL the material you need for the time you are going to play the game (and that must be defined game-wise rather than 'lets see how we go') then I would say it might work for you better than something else.'
However, I think that the above applies to a small fraction of RPGers and that fraction is likely to only get smaller. As I said before it was a specialist and I see the call for its specialisation as being on the decline.
For most people I'd say 'Get something in the current arc of the game. If need be use older stuff thats useful in its place - be that from CT, MegaT, TNE, GURPSTrav or T20'.
I can think of at least several bits I got from use with T20, or from other version for use with T20 that Ill use in the future with Mongoose's Traveller, but in general I think you'll get better compatibility with non-T20 stuff, and obviously the best compatibility with the current active product.