If you are going to use a EVO, I would just go with Zap Unlimited. http://zappunlimited.com/default.aspx
You can bring your own device, any sprint phone with a good ESN. That would be the best route for you. Then, you wouldn't have to worry about getting cut off. And, last but not least, it's only 49.95 for the same plan, but without tax. My ST card cost me 48.15 with tax, so this would be whopping 1.85 more for a little peace of mind. All of this of course is contingent upon Sprint coverage working for you.
I have a Fascinate flashed to ST. I have just ran out of my time on it, so I'm probably going to sell it and get a EVO. Sprint coverage works fine for my travels. I didn't have any trouble with it though last month. But, I didn't hog data either. When I was at the office or home, I kept it on Wi-Fi. I did run a couple of speed test on it, and got typical 3G speeds 1.2-1.5- mbs download. I just feel better going with ZAP myself, but it is a personal choice.
PLEASE, don't PM me with questions that could and should be answered in the open forum. Then everyone can benefit from the answer, and you will get more than "one" opinion... Thanks.