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This is my 1st post here and it may even be a bit off topic to this forum.
However I thought I'd post my experiences here, as it might be one of the forum sources people find, before they buy.

I am a sound recordist for film and TV productions and in this industry we use AA NiMh a lot for wireless microphone transmitters, and IFB lines. It becomes a bit less in the past years as more and more manufacturers switch to Lithium based proprietary formats, but never the less, here is what I can tell.
I operate 2 ISDT N24 chargers with 48 (white) Ikea LADDA 2450.
As a charger, they have not failed me, and though they are quite expensive, compared to other chargers, I do not regret buying them. Especially the ability to set charging rate and overall power consumption is a really cool feature. So far, I have not tested, if limiting the overall power consumption actually works.

What you should know:
- These N24 make a high pitched noise. Depending on your age and hearing that may or may not be an issue, but you might not want to operate them overnight in your hotel room or during the day in an office.
- ISDT advertises that firmware updates are possible, but no new firmware has come out as of yet since I've bought them. I doubt it is in active development, though there is quite some room to improve usability and ergonomy.
- When analyzing finishes, the display outputs only the charged mAh, not the previous discharge value.

When I bought my N24, I hoped that with some new firmware, there would be a possibility to read out the data of analysis session from the usb port, e.g. as a CSV or similar. As of now the USB port is of no use, unless for a future firmware update, that I'd doubt will come.
The other day, I've run an analysis session for all my 48 Laddas and manually copied the charging capacity into a spreadsheet (and resistance), to see what would be a good threshold for worn out Laddas and mark them as "mid-aged". I've used 300mA to keep everything not too warm. My Laddas have been on duty very randomly are a few years old and have not passed many charging cycles. They have been charged not over 700mA, mostly 500mA or so. (Slow charging keeps your NiMh fit.) Therefore I expected some quite different values. I've sorted the data in an ascending way and made a graph. Great, somewhere around 2800mAh seem to indicate aged or untrained units:

...Until, I've sorted the data back to the position in the charger. Wait, what???

There is an unexpected pattern, that matches the six blocks of eight bays architecture of the two N24 chargers. Probably, heat distribution distorts the measurement significantly. My conclusion is, that this thing is not really useful for analysing batteries, at least, not fully loaded and I need to analyse with my 4 bay Maha C9000.