Alesis Ion

Pros
Very fast FPGA logic, with very low aliasing
Three oscillators with 3 variable waveforms
Dual multimode filter, with several emulations (4-pole Moog Ladder, 2-pole Oberheim, 4-pole ARP, 4-pole Jupiter-8 and more)
Noise, S&H, Arpeggiator
Lots of LED indicators, e.g. "in tune" OSC tuning kobs
All rotating controls are endless potentiometers, not encoders
By changing program, old notes are leaved with old timbre
Stylish and very compact size
Two illuminated modulation wheels plus pitch bend one

Cons
Very ****ty keyboard (Fatar TP7, full plastic)
4 octaves only
Unusable effects
No aftertouch (it does receive both channel- and poly-aftertouch)
Detailed display is flat with the case, and unreadable by seated player
Frequent damage of output FET muting transistors (easy and quick to repair)

I find the Ion a sort of swiss knife in most occasions; controls on panel give quick access to all main parameters, without digging in menus. The sound has a good character and the dual filtering allow creation of complex sounds.

I've replaced the horrible keyboard with an excellent Fatar TP9/S with aftertouch; the cables are straight compatible: it needs to make the right holes in the base, and to add a MIDI analog encoder to route aftertouch in MIDI in.
The modified instrument becomes a very pleasant one; the new keyboard protrudes on front of about 8mm and the instrument weight increases of about 1,5kg.