A while ago I bought a Korg Micro Key on E-Bay. It was a 25 key version and was going for a very reasonable price (£25) and I was looking for a small keyboard to go on my desk as my main large (76 key) board - a CMI UF7 was now positioned right behind me ( I know.. bad studio Feng Shui).
Sausages to keys ratio
To be honest I wasn't expecting much as I have fingers like sausages (i.e fat) and pretty much expected to try the keys out once and then resell them on back E-bay. Well, I was pleasantly surprised; the keys aren't to small at all and I can quite easily use it for chords and runs with no problem at all. In fact I've been so happy with it I managed to grab a full 61 key version recently - my daughters happy too as she now has the 25 key model to use on the Ipad with Garageband.