I'm a big fan of 3/4" plywood. I get 3/4" A/B birch-face at about $65 a sheet at my local home depot, it doesn't have many voids, and it doesn't take an insane amount of work to get an adequatel (not Ond-level) paintjob on it. It's lighter and stronger, if it ever gets wet it won't become oatmeal, and the sawdust isn't evil.
(Well, ok, it isn't actually 3/4, it's something absurd like 35/48ths inch because plywood sizing is stupid - but it's basically 3/4, close enough that T-mold looks alright.)