I know there have been a few fails, but considering the amount out there and the amount of cars they are in. Thats not many.
The AR35 in my Senator is still silky smooth @ 141k miles, and no noise from it.
Without maintenance any box will fail, but the boxes by GM have been quoted as the finest in the world.
The rate at which my Senator goes from 30 up to 3 figures is incredible.... why you need anything more powerful than that for regular road use is beyond me! :-/
The point is that, generally manual boxes do not fail, and require little to no maintenance. The oil in my BMW's gearbox does not require to be changed for the life of the car, I was sceptical so had it changed last time the car was in for a service. The oil that came out was the same pink/red as the new stuff! I expect the Omega gearbox is similar - mine is on 168k and does not get an easy life, it's just had a new clutch that will probably allow it to do another 150k with no maintenance, assuming the engine lasts that long!
BTW There are websites claiming the Rover K-series is the finest 4 cylinder engine in the world, maybe you should ask TheBoy what his thoughts are on that one
"finest in the world" quotes are ten a penny, personally I don't take them at face value.
Your senator's acceleration is only incredible to you because you're not used to it yet. I'm not knocking it, but believe me you'll get used to it and it won't feel particularly impressive any more. I thought the same thing when I got a 280 BHP Impreza at 22, wow phenomenal acceleration, but soon enough it became "normal". That would do 0-100 in under 13 seconds, but after a while it didn't feel that special. Hence why a manual 3.0 Omega doesn't feel fast at all, even though it's the fastest model you could buy (with the exception of the cop-only 3.2 manual). You don't "need" anything faster than a Daewoo Matiz for road driving, but power is nice especially when you get onto the twisty B-roads. It's not all about straight line acceleration, being able to effectively make use of the power is where it's fun.