I received text messages when I had my Nextel 7510 and I still receive them with my 7520. I was not able to REPLY as an SMS though and had to reply using e-mail. As well, when you receive SMS, you have no idea where they are coming from because they do not show the sender's phone number. E-mail is definitely the preferred method of comunnication if you have your berry through Nextel.
As well, I'm sure you know what you're up to but I assume you have a voice plan on your Bberry? If you have both the voice plan and the data plan, you will receive a $5 discount making it approx $34.99 for the 5MB plan and $44.99 for the Unlimited. I do not know how much you text but you have "pay-as-you-go" text messaging with that $10.00 data plan and that's scary. I eat 500 texts for breakfast. You're already paying $10 and you could 1. Be legit
2. Not need to worry about counting messages 3. Have the benefits of the BIS e-mail service - which surely you must be missing and a whole bunch of stuff I'm not smart enough to figure out all for an additional $24.99 or $34.99. Not to mention that the first month you receive over 250 messages (not a lot when you get rolling), you've already negated the benefits of circumventing the system with your $10 plan.
Just food for thought...