Alright lol everyone chill.
The x1 signal quality is the old CDMA service and generally allows for basic phone calls, SMS, etc. When you're in a good enough area to receive 3G, you can start doing things like streaming YouTube, MMS, etc. If you have a signal at all, and you aren't roaming, then you will always have a x1 connection. It's just that sometimes the signal isn't strong enough to allow for 3G on top of it.
It really doesn't matter what carrier you go with, you will always have times where all you can get is the old x1 signal. Some carriers have better coverage, but tbh, I think Verizon probably has the best service right now in terms of 3G coverage. I'm only basing this from using or borrowing friends' and family members' phones that have service with another carrier. I don't think I've ever had a bad experience with Verizon coverage before. Even if I hit a low signal area, I can easily find a 3G connection shortly after, sometimes without even moving.
Good luck with T-Mobile, blown-droid, if that's who you decide to go with. I've heard they're pretty good but I can't vouch for them personally. I've only ever had Verizon before.