I have not built either model, but I have the Meng T-90 and the Trumpeter T-72, which still has T-90 parts on the sprues.
One thing Trumpeter has done better than Meng are the wide retaining straps on the fenders for the fuel tanks on one side and storage boxes on the other, which are separate etched straps with tiny plastic bolts. I would assume that they have done the same on their T-90. Meng has molded these solid. Still nice, but Trumpeter does beat them for detail in that particular area.
Then again, this is now possible to "rectify" on the Meng kit with the new Miniarm fuel tanks and boxes, which include the etched straps.
/Sven