VIP by Akai is a tremendous idea, being implemented increasingly well. Now it's up to version 3.1. Coolest yet -- it's available for usage beyond just the 3 original InMusic brand keyboards (Akai Advance, M-Audio CTRL-49 and Alesis' offering). Think of it as an advanced Browser & Mixer combo that allows you to preview, control, layer, and mix among multiple soft-synths and also supplement them with your favorite VST2 effects. Easy to find optimal patches. Easy to layer ginormous sounds. Useful in stand alone mode. Also integratabtle into DAWs. I'm still learning to play with it, mainly within Samplitude.
Trying it out both with an Akai Advance (seamless, but quirky) and with a Novation SL49 Mkii (usable, but not seamless, and the knobs seem to work backwards and don't automatically correspond to onscreen knobs). The Win10 software is still inconsistent. I've had some crashes and some disconnects between the Akai keyboard and the VIP software.
The concept is AWESOME. Seems there are still bugs to be worked out. Haven't yet tried the Mac version. The software package is nice. I already had 3 of the main players from PIB, so not quite the value for me as someone getting the entire SW package of synths and effects included. At this $100 off, the SW is a no-brainer. Akai has invited other manufacturers to now do their own routing (more like NKS), so that should expand the number of synths and manufacturers who embrace VIP.