All you have to do is read the posts here and other Droid X forums including the Motorola Owners forum. While all phones have their issues, the Droid X has had several and more on Gingerbread. I was so frustrated with how bad the X was on GB that I reverted to Froyo and have been happy since.
The Verizon person is uninformed. There are a lot of angry unhappy users of the Droid X (sure, there are plenty of those who are totally happy) but it's impossible to know what the true percentage is. You have to assume that users of smartphones are a technical bunch and, if they have problems, know how to search and post on the internet.
All I can say is that there are a LOT of posts about problems with the X spontaneously rebooting, starting up when you just turned it off, rebooting while playing music, keyboard problems, Wi-Fi connection problems, and 1X instead of 3G connections. For every goofball who has to post "I haven't seen one issue with my X and it's wonderful" I'm sure I've seen 5-10 disgusted users. But that's true of any phone.
I also think there are a lot of faulty phones that have been "refurbished" that are not actually fixed and Verizon is simply passing on the problems to the next user of that phone. MY phone is great on Froyo but a POS on Gingerbread.
Good luck with your new one.