I'm happy with Acera, no problems. Alivio should shift VERY nice. If you need "better shifting", perhaps all you need is clean, re adjust and perhaps new chain and cassette.

If you really want something more expensive, do not go over Deore. Unless you're racing that is. Also, I'd suggest you stick to 9 sprockets in the rear, or use a chance to downgrade to 8 if you're changing it all now. More reliable and cheaper in the long run to maintain.