Right now if you want to take advantage the new Multidimensional MIDI expression, MPE or 5D touch as ROLI Seaboard call it, (see our review) or the Roger Linn Designs Linnstrument are your options.
Roger's unique design features 200 RGB backlit, pressure, velocity and position sensitive pads. It's laid out in a kind of guitar string way with 8 rows of 25 buttons with each row having a 4th interval between them. There's also a left hand side row of 8 modifier buttons to access additional features.
Connections are MIDI I/O, USB, power (7-12v) and dual pedal input for switch or controller.
The Linnstrument can be set to transmit over MIDI or USB but sadly not both at the same time.
Setup is handled by clever use of the RGB lights and using the buttons themselves to handle value and inputting data, such as MIDI channel setup, pressure and position CC, we particularly like the display of numeric values with swiping for up/down.
The Linnstrument can be setup to transmit MIDI over four channels as per the MPE spec (notes round robin over each channel) that way pitch bend , X/Y button position are per note per channel and allow for extremely expressive playing.
All the controller data is freely assignable, as are the pads in terms of MIDI channel groupings or single channel mode.
There's no doubt that as with many alternative MIDI playing devices, you're going to need to work at it to become fluent, but expression is something that you will appreciate from the beginning, the Linnstrument is a very naturally responsive thing for sure. As Gaz says, it will though require a LOT of practice time to be able to get the most from this. But the applications are more immediate than with something like the ROLI - with a MIDI output, you can access hardware directly without the need for a computer.
Additionally, USB allows you to hook up an iPad to play Moog's Animoog, System 55 or Wolfgang Palms Wavemapper. When you do this, be sure to set the app up to use 24 semitone pitch range and MPE mode. When hooked up to iOS, Linnstrument will work in low power mode with less bright LEDs. Animoog, has some excellent patches that demonstrate this.
The other cool function of the Linnstrument is that you can split the surface to have two separate playing areas with custom split point. Additionally, you can set one of the split areas to represent custom fader controls, transmitting assignable MIDI CCs. It is also possible to set a row to transmit per channel, or make the bottom row to send sustain commands or retrigger notes for strum like effects.
Do You Need It?
One thing about any of these new controllers, is that the level expression is astonishing, it has to be played to be appreciated, it's not something that can be explained. The Linnstrument offers a higher degree of connectivity than the ROLI which makes it a more open system. It's a shame that the 200 buttons only send note data though (CC switch mode would be awesome) and that there is only a single split, more would make it even more powerful. But the bottom line is that it's a beautifully made piece of hardware. It not a cheap thing, at around £1249 in the UK from dealers or $1499 from the http://www.rogerlinndesignstore.com/ which includes free worldwide shipping - if you ask nicely, Roger will sign it for you too.