My organization has been using the Juno 3-series devices for a few years and recently bought two Juno 5-series (one running Windows Embedded Handheld and the other running Android 4.1) to test.
Bottom line is this - I simply can't recommend the Juno 5/T41 devices at this time. The problem isn't the hardware. In fact, the hardware is outstanding. Trimble stumbled badly with both versions of the device when it comes to operating system choices.
First, Windows Embedded Handheld 6.5 (WEHH) is a dead OS. While I understand that the new Windows 8 Mobile OS was not (and really still isn't) ready for prime-time when this unit was developed, and ESRI has yet to port ArcPad over to Windows 8 Mobile (if they ever do), the fact remains that WEHH is an archaic, under performing OS in today's market and it's poor performance really shows on the Juno 5 hardware platform. It's like putting a 4-cylinder Yugo engine in a Porsche. Heck, we can't even get these devices to sync properly with Windows 8 desktops. It's time both Trimble and ESRI leave WEHH behind and begin development against a more current mobile OS.
But Trimble stumbled even worse with it's Android implementation. This is the OS we really had hopes for. The ability to run ESRI's ArcGIS and Collector apps, Trimble's own TerraFlex, and take advantage of a whole host of other enabling apps like Google Earth, Google Docs, etc. really appealed to us. The problem is that Trimble did not move to get their implementation of Android certified by Google, so no access to the Play Store; no ESRI apps, no Google Earth, no Google Docs. Heck, the units can't even run Trimble's own TerraFlex app! Our distributor told us that Trimble is 'rushing' to get the Juno 5 certified by Google so it can access the Play Store, but they've been 'rushing' for months now and still no word on when or if this certification will ever take place.
So we have turned back to the Juno 3 platform until Trimble gets this all sorted out. Our experience is that the Juno 3 is a reliable, stable and rugged platform. We've had very few issues with them running ArcPad. Hardware performance may not be the best, particularly camera performance, but it's still a viable platform and it comes in at about half the cost of a Juno 5.