The 2B would certainly give you more versatility, since you can:
+ control it via a serial connection.
+ connect it to mains power via an adapter and saving many batteries in the process.
+ be sure that the 2B has proper electronic separation between the channels, thereby avoiding current flow between the channels.
+ use patterns with another modifier control, next to the feel.
I cannot tell if the Pebble has less or more power than the 2B, since I have never experienced the Pebble for myself.
On the other hand, you might want to keep the Pebble as well.
The Pebble has a knob to control the feel of the pattern selected without having to press the select button (on the 2B) simultaneously.
Pressing the select button too long will result in a mode that will cut the power and allow you to select another mode.
This is one of the reasons why I bought the E2B
in addition to my Series 1, rather than selling the Series 1 to someone else.
the series 1 also sports a jolt button, which can be quite handy to have when you want to surprise your play partner
