When I went into my evaluation for them, I had to look at purchasing a product that would not only be scalable for an ever-growing BES environment but also scalable for an ever-growing support environment. We were picking a product that would be used by my team of engineers and administrators, as well as one that could be used by our systems operations center, network operations center, deskside support personnel, and help desk and customer support center, as well as upper management for pulling reports. This means that a few hundred people would be using the solution - not exactly feasible for an application-based solution and why a web-based interface was my number one requirement. Spreading the use across multiple departments allows for either a capital expenditure or a multi-department spread of expenses ...definitely helps with the bugetary numbers.
The only reason Zenprise ever made it into our doors was because I was told on the phone that they had a web-based solution. During their presentation, they backtracked on this and said they *might* do one later on but it wasn't in their plans at that time. The BlackBerry module for their product suite was built and put to market in 90 days. It's a work-in-progress that is not honestly worth it's price tag (even at the 'giveaway' prices they're offering). Reporting is based on SNMP data which may or may not accurately reflect the log data they capture in the application. Solutions for issues are pulled from RIM and Microsoft KB articles and are not customizable for in-house solutions that are gathered from experience, message boards (such as BBF), etc.
We have recently decided to go with BoxTone. Initially, the money involved was a concern. Management was sold after Dan and Jon's presentation, although I still tasked myself with evaluating other products, Zenprise being one of them. BoxTone has it's faults, but they are far outweighed by the positives (web-based interface, drill-down abilities, Help Desk module and ping tests, customizable alerting, custom-configurable groups, etc). They also have a development team and product manager who are more than willing to bend over backwards to fix issues and add new enhancements and fulfill feature requests.
Give them both a call and have them come in for a presentation (or even do a web demo). It'll give a fairly accurate view of what each has to offer and should only take up 1-3 hours of your time total. I honestly fell asleep during Zenprise's on-site presentation, but that's neither here nor there...