when you first read of this one, you may be sceptical: a multi-effects unit for under $400, how good can it be, all the good ones cost at least $1k.
well, believe it, the Lexicon MX400 (available with trs balacned or xlr), which replaces the MXP550, is an impressive unit - the reverbs are actually pretty good, though not as defined in depth as the Lexicon PCM series, are excellent for live and high enough quality for basic studio usage - the unit can be linked via a vst plug-in to usb and controlled just as you would any audio plug-in with the exception that the sound is routed directly through the unit making it have zero latency, a problem often encountered with using software plug-ins live. the application of this in live usage controlled by a host program, like ableton LIVE, is perfect solution for vocals and other sources; my previous attempts at routing effects via software for sequencing and remote control were meet with an unusable latency using a firewire sound card and a macbook pro.
i used the mx400 mainly for an electric cello, and at first i routed it externally so it accessed all 4 possible effect banks at the same time, this gave adequate results and permitted to use 4 different effects, but it limited the function of these effects and the sound was not as good. when i later set it to basic single channel and used a single effect program, i found the reverbs very suitable for this usage - they were full and realistic sounding.
overall, i found the unit excellent. while it is not a replacement for the lexicon PCM reverb software via dedicated hardware of software, or an eventide, it is a very good solution for live instrument and vocal usage. while unit has 4 processors and can handle quad (dual stereo) channels, it gives the best sound and function as a stereo unit. if you are sending this into a pa mixer or instrument amp loop that is going into pa mains or an instrument cabinet, you will be very happy with this unit. if you are doing studio recording and previewing on high end monitors or headphones, you will find it just passable, but cannot complain because it still sounds exceptional for the $300 - $350 you paid for it and is good enough for cd production.
excellent sounding reverbs when in stereo single effect usage
good delays and sync
usb with plug-in control
dual spdif ports
pitch effects work in full range, not just for guitars
can be routed in mono as well as balanced stereo and 4 channel surround
no basic parametric type eq programs
chorus does not sound very realistic and not a replacement for a good stomp box.
reverbs lack a certain depth when used in surround/dual channel mode