Depends on your cable service. I know my roadrunner is a bit slower than my comcast cable.
If this is the service you're referring to,http://www.verizonwireless.com/b2c/mobileoptions/broadband/serviceoverview.jsp
It will be signifigantly slower than cable. most cable is at least 3Mbs, and verizon says average download speeds are 400-700kbps, which is .4-.7 Mbs.
Whether or not it's worth it depends on how bad you need it.