I will start off by saying I have owned a KORG Monotron (original) for a few years or more (since they 1st came out) and always loved being able to get such a variety of synth sounds from a pocket sized instrument. I have only used this new Monotron Delay for a few hours so far but it exceeds my expectations.

I had a little bit of trouble getting it to work at 1st. Almost no sound would come out and I worried that I got a defective unit.. I adjusted the volume all the way up, nothing, tried again, nothing... I changed the (included) batteries for known good ones and still nothing... Finally, thru adjusting the settings, I realized that the cutoff knob needed to be adjusted as it was preventing any sound from being produced.. Half way up produces sound on most settings..

Once I got it working, I didn't want to stop using it and only quit when it was time to eat lunch.. I am about to try it out again and probably won't quit until I figure out some more great sounding settings...

Absolutely fantastic if you know what you're getting yourself into. I bought the delay expecting not to use the actual synthesizer very often. I expected to mostly just run a keyboard of mine (the Arturia MicroBrute Analog Synthesizer, which I also highly recommend) through the filter and delay. It's great for doing that.
Also, before I launch into my full review, I feel that it's important to talk about battery life. I've had the thing for about 2 months now and I use it about an hour a day. I go through about 8 AAA batteries a month.
However, what I didn't expect were the surprisingly musical synth noises I've been able to coerce out of this thing. Don't come in expecting to be able to play real melodies on this thing. The keyboard/touchpad thing is only a couple inches wide and spans at least 4 or 5 octaves. What I found is that it's great for producing drones and effects. I recommend holding down a point in the middle of the keyboard with something like a guitar capo and tuning it with the LFO and INT knobs, turning the LFO up so that the LFO is actually making the sound.
Now as for the delay effect itself, it's dirty and noisy, but if this isn't the first review you've read, you probably already heard that. What you may not have heard is how fun and actually useful the grit and feedback properties of the delay actually are. Recently, I've had a lot of luck turning the time way down and the feedback up to a point where it almost won't fade. It's good for something like a long spring reverb type sound.
TLDR; I love this nasty little effects unit. At 50$ you'd be amiss not picking one of these up to put between your raw synth and your amp.

Korg Monotron is ok and fun to play with, but not much more than that. I had one when they first came out and sold it about a year later. The models of these mini synths from Korg got more interesting as they evolved and came onto the market but most of them are kinda like this one.
One trick ponies if you ask me, but I think they DO have a place in the world of electronica. Personally, id rather have a more capable machine to get my Analogue sounds in order, however, this sure is a way to do it, just perhaps not the most eloquent way to do it. This is a real basic device that can teach you a few things and could even be useful for the right person who is building a small mini synth collection. For the working DJ, it may provide just what you need, an occasional blast of Analogue flavoring, but if you are using it in the studio, you may want more features.

Noisy little synth that's not a toy. I've been sending it thru a echo unit and getting some really great results. There is a little hiss present which I believe comes from the filter but in this day of clean digital music a little bit of noise adds character.

this is the size of an adult hand, but it is still very dangerous. at first i was skeptical, granted i have only dabbled in this kind of thing up until now; but if you hit the keys in the right order and with the right sequence, you can open the portal that allows contact with the s'ngai bra'h nak. i had a partner who assisted with this, i advise you to have a partner as well just in case things do not go as planned. regardless, it is a small, compact size with a danger factor of 10 and capable of unlocking many portals.