You running Gas or diesel? Were you getting one just for the digital gauges, performance tunes or both? I have heard good and bad things about Bully Dogs. There are those who love them and those who say they are no good. I myself use an Edge Insight that plugs into the ODB (OBD) port and can monitor about everything. For EGT temps (for Diesel), you have to purchase and have the EGT probe installed separately. There are other brands of digital gauges available also.
For performance I use a Smarty Jr. For Cummins, Smarty and H&S are the 2 most recommended tuners. EFI Live is fast growing.
You may want to look into some of the diesel forums and do a little research as to what is said about the various tuners etc. Dodge Owners Forum http://www.dodgeownerforums.com
is one that I belong to.