I have both the 7100t and the 7230. My 7100t has been replaced 3 times by T-Mobile. Only upon threatening to take my business elsewhere, they sent me the 7230 to retain me as a customer.
Besides the well known re-boot problem with the 7100t, I experienced frequent network signal loss with the device not being able to log on to the network even when other devices were showing strong signal. Tier 2 and RIM tech support gave up. IMO, there is an antenna problem with the device and RIM has not fully gone to the mat in testing it fully.
I miss the speakerphone, the bright screen and phone interface but would not trade that for reliability since I am on the road weeks at a time.
