Hi!
My personal recommendation is clearly the HP25xxC. Of all the consoles available, this one has the widest range of features. It supports all currently available sensors, has the option of an SD card for saving all data as CSV and goodies such as time-dependent activation/deactivation of the display and (in the latest version) probably also supports the http API.
The console requires approx. 450mA with the display switched on at 5V and approx. 170mA with the display switched off.
All these things should also apply to the HP2560C - but I have not used it myself and can therefore only recommend it with reservations - others with direct experience should be able to say more.
I also have the HP3500C here. However, it is clearly limited (even in size - it is really tiny!). It has the basic advantage that you can also connect it to a PC via USB - but the implementation is somewhat unkind and the console is hardly maintained on the firmware side. At least it supports all sensors (although I'm not sure about the WN35) and also the additional storage of data on a microSD card.
I have not yet measured the power consumption.
My "secret tip" for those for whom the HP25xxC is too expensive or too big, or for whom less content in the display is enough, or who are just looking for a second console, is the WN1980C. I had also written a
review about it somewhere here.
However, if you are basically satisfied with your current console and also use the possibility of remote data reading via WIFI, you can simply exchange the sensors that may be dying little by little. Or you can simply continue to use the old console in parallel - this should work with most standard sensors. Note, however, that old and new devices must operate on the same frequency.
Oliver