Yes, I agree. One of the best app I got. Can't imagine using Axim without it.
I am surprised you couldn't find too much discussion about Pocket Plus. Its release caused quite a splash, way back then.
BTW, rumor has it that since Pocket Plus is so tightly tied in with Pocket PC 2002, some features do not work in Windows Mobile 2003 environment. But I am sure Spb will come up with a new release for 2003 if this is indeed the case.
**update**
Should've checked Spb website before I posted

.
The following is on the Pocket Plus FAQs
"18. When will the upgrade for Windows Mobile 2003 for Pocket PC be available?
(June 30, 2003) - We are now working on a new update for Pocket Plus that would support Windows Mobile 2003 based devices and fix known problems with current version as well. The new version will be released as soon as it is finished and passes all the testing. "