Again, with Jerry C's generosity, I finally got some time to play with a SPROG-IIv3 unit at home with my newly TCS decoder-enabled Geep. I've learned a heck of a lot more about this really compact system and I'm now fairly well decided on the direction I'm going to take with my DCC system purchase.
To start with, I learned the hard way that when switching the SPROG-IIv3 between its two modes: SPROG mode for programming and SPROG Command Station Mode for running trains, you must cycle power on the SPROG unit to clear it after any programming track activity or something that is going on between the SPROG and JMRI software will inhibit your ability to run your loco at normal throttle settings. The manual does point out that a power cycle is required but the note can easily be overlooked, and it is not obvious why it should be necessary but alas it is seemingly very crucial to proper operation. I even found that just reading some CVs in programming mode followed by pulling up a single throttle would limit my throttle range of the loco to roughly 1/4 of the full range. So ... always power cycle the SPROG after any programming activity and all seems to operate fine after that :o).
As you can see, the SPROG unit is rather small, especially when compared to the NCE Power Station that I've been also evaluating. All of the SPROG units, boosters included, are using the same packaging so even a complete system doesn't take up all that much space.
So ... decision time ... now that I've had a chance to play with both systems, the plan that I talked about earlier with the SPROG-IIv3 feeding two SPROG boosters is the direction I plan to take for my home use. It remains to be seen what we will choose to use at the train shows as some of my group already have NCE systems and for the much larger layouts, the extra power capacity of the NCE might be a benefit. For my home arrangement, going with the SPROG limits me to 2.5 amps per district and I'll have to implement a switch arrangement to deal with the programming track but these relatively minor limitations don't seem enough to justify spending double to get the NCE. I may ultimately get a separate SPROG-IIv3 to dedicate to the programming track if I really find it inconvenient sharing one between programming and mainline operations.