I think engineering is awesome so far, i recently started a new toon and took the quick path to 200 engineering. I made a spredsheet a while back that showed you could power-level to 200 engineering with as little as 33g gross investment (I say "gross" investment because it doesn't account for selling any of your items, which can reduce your net cost). I got a bunch of neat headgear (most recently spellcaster goggles xtreme), some cool pets (exploding sheep, harvesters, dragonling), and other trinkets (discombobulator ray, jumper cables, net-o-matic) that made the whole thing pretty worthwhile.
The biggest downside to engineering is that it isn't a real moneymaking profesison. The only way to get cash from your tradeskills then is to see your mining ore and stones. If you're 300 blacksmithing i imagine you're pretty far along with your toon (probly level 55+) so i would highly recommend it as money likely isn't a major concern for you. If you've got your epic mount, then engineering would probably give you a nice new sink to put your money in since there's little else for you to save up for and will give you that little extra advantage and extra fun.