The LPK25 is an item I purchased to complement my OTHER purchase of the Akai LPD8. Since I travel a lot, these are fantastic for putting them into my carry on bag.
The LPK25 has a small footprint, and as such the keys are obviously too small to use in the same manner as a full sized keyboard. However, I don't count it against the unit. It does, however, have some flexibility with the included driver and software to save presets which is invaluable to any user. The keys are responsive and I was very surprised at how well they translate velocity information into my DAW software. Extremely accurate overall. The only slight issue is that some of the keys seem to be slightly more or less responsive than others. But for the price, and the intended use, this isn't as big of a problem as it would be for a normal sized keyboard.
Overall I find it to be extremely useful for getting my ideas down when I'm on the go. If I broke, or lost the unit I would definitely buy a replacement for it.