They are all an own breed by KORG. They are in no way comparable to existing BOSS pedals. I have had them all, with the exception of the CMP-1 Compressor and the NGT-1 Noise Gate.
CHR-1 Chorus
A totally different chorus effect in comparison to the CE-2. The CE-2 offers a very strong effect in every setting so that I prefer the CE-2B with the effect volume knob. The CHR-1 can get a bit in the CE-2B territory, but the overall effect is different. I think that the BBD chip has a shorter delay time, hence the flanger sounds that are possible with that switch. Oh, and it has a great vibrato sound if you put a dummy plug in the stereo out jack. Demo
here.
DST-1 Distortion and
DST-3 Hard Dist are mentioned in the quoted post above.
FLG-1 Flanger
Again a pedal that looks like a BOSS pedal at first glance, but the sound is not like a BF-2. The FLG-1 is a really wild thing with deeeeep flanging sounds (longer BBD delay time, I suppose) and a factory-set ability to oscillate like crazy. I really prefer this one over any BOSS flanger,
even the BF-1! Demo
here.
LIM-1 Limiter
I received this one a few weeks ago. It is a good pedal which does a nice job, but the effect is more gentle than that of a BOSS LM-2. Or better said: the LM-2 is able to create much heavier limiter effects. The LIM-1 is a "set and forget" pedal: once dialled in it is perfect for your funk bass tunes. It has a lot of headroom in store and takes very high signals, which makes it also a good pedal for keyboards.
Korg OCT-1 Octaver
I really LOVE it! It offers only a one octave down effect, but it is such a powerful sound that you don't need a second octave down mode. Although nathanscribe might not agree I think that the tracking is phenomenal: it goes all the way down to the low E of a bass guitar. The polarity switch makes tracking either better or not. The function is only vagely described in the manual and nathanscribe tried to explain to me what can be read in the schematics. If I remember it correctly the input signal undergoes a 180°phase inversion so that the octaver circuit can work more accurately. Anyway, in mode "A" it's awesome with my Jazz Bass and mode "B" is great for my guitars. A demo will definitely follow later this year.
Korg OVD-1 Overdrive
This is by far my favourite pedal of this KORG series. It produces such a lovely overdrive sound with a lot of tube amp character. In my eyes (or ears) it is perfect. It doesn't have the mid-hump of a Tube Screamer (which I always found annoying). It rather shares a bit of the BOSS OD-1 sound, but with a more lively sound and lots of warmth. A demo is in the making and will also be published later this year.
Korg PEQ-1 Parametric EQ
As you know I received a BOSS SP-1 Spectrum a few months ago. Well, the KORG PEQ-1 is pretty much like an enhanced SP-1 with an added Q knob, called "Bandwidth". I really shouldn't have sold it, but I need money at that time when I did. A very rough demo
here.
Korg PHS-1 Phaser
A simple two-knobber. At first glance you think it might be based on the BOSS PH-1, but it is not. I had the PH-1R a while ago and the PHS-1 has only some sonic overlap for the fact that both models work with 4 stage phasing. I think that it rather shares a bit with the EHX Small Stone sound (without the resonance mode). I like it a lot. It is a good workhorse if you want that distinct '70s tone and I definitely prefer it over the BOSS PH-1(R). A demo will follow in the next months.
Korg TNB-1 Tone Booster
What. A. Beast. When I heard that this booster is capable of producing a rough overdrive sound on its own I clearly HAD to buy one. And I didn't regret it. The overdrive sound is quite unique (fuzzbuzzfuzz said that it gained some cult status in Japan) and the clean boost functions are very versatile. Demo
here.