I just downgraded back to .175 today as well. Was experiencing terrible lag/hourglassing. The memory leak was too much for me to deal with. I hated it when I had the 8830 and I was glad I didn't have to really worry about it on the 8330 until 5.0.
It's easy to downgrade:
How do I downgrade the OS on my BlackBerry? - BlackBerryFAQ