I'm not sure how feasible it is to dismantle an iPhone or iPad and read data directly off the flash chip. My current understanding is that with the 3GS and above, all data on that flash chip is always encrypted, but I don't know how secure the key is.

It's currently easier with the iPhone to just jailbreak the device to get around the protection, even with the latest 4.3.2 release. For now, the iPad 2 has yet to be broken in that way, so I put a little more trust in it.

Security wise with my company, a compromised phone would at most get someone access to my e-mail. Anything worth accessing is protected in other ways that can be locked down quickly. E-mail could also be wiped, leaving someone with just the cached past few days worth of messages on the device. I do also have both active with the Find my iPhone service, allowing a wipe command to be sent over the air.