It's interesting how the Roland EF-303 has a bit of a love/hate following; this reminds me of Behringer gear, the Korg KARMA, or a Yamaha DJX. You can certainly read the spec's elsewhere, so i'll try to keep this short and ignore said specs.
Bottom Line, i think the person who'd get the most out of this is one who already has a wealth of gear. In my particular case i already own about 30 keyboards/synths (not even counting the rack stuff!), melodicas, monotrons, mandolins, ukes, guitars, etc etc et al ad nauseum. I remember when i got this thing i just didn't know what to do with it for a few months and was kinda bummed 'cause it was, well.. yet another piece of gear that might sit around unused and i'm getting a little tired of buying crap that just *sits around*. (Yeah, i know that might sound a tad neurotic!) It seemed pointless to run an Electribe or something through it as why couldn't i just use an effects pedal for that and save a little space?
Eventually the EF-303 ended up being a big part of one of my larger rigs at home. It sits among a great bunch of gear and i usually just run my laptop's audio through it (so that the laptop's audio gets the whole "home stereo system" treatment of big booming sound, etc.) For a while i just fooled around with treating YouTube videos' audio with the effects. Nowadays i like to use that laptop cable (i.e., 1/8" to RCA connectors in the back of the 303) and just plug WHATEVER in there -- monotron, mp3 player, drum machine, synth, etc. I also keep a mic on a little tabletop stand hardwired in the back as well. Sh*t! I am just now remembering that that's what that mic has been sitting there for, LOL !!!
I suppose this thing is a bit of a "Jack of All Trades, Master of None" in that you ahem, only get so much effect-wise. That being said, having all these effects in one box -- and a good bit of control over them -- is much more than i would have dreamed of 20 years ago. Tap-tempo-sync'ing of the effects is something you don't always get on some synth/sampler workstations even now, and when you you throw in the TB-303 emulator and vocoder effects it still seems like a real no-brainer purchase to this guy.
I got mine for about $125 off eBay in 2014 and now that it's found its place(s) i am extremely pleased to have it. People seem to be shedding them on the 'Bay right now so you can probably find one for less if you're patient enough to watch them for a few months...
See below for the list of effects. Personally, I use it mainly as a syncable resonant filter but also as a MIDI step sequencer (it even sends notes...).
No PC editing, it's not rack-mountable, very digital, jack in for a mic, RCA for line or phono (it has a built-in RIAA preamp). RCA output. Midi In and Out.
Everything is relatively simple and can be easily edited. The manual is clear and you might need to read it thoroughly to learn how to get the best out of the unit!
Effects are digital and a bit dated, so they can seem a bit cheap. But the fact that the effect can be synced to the MIDI tempo makes this machine really useful.
In the worst case, you can avoid the internal effects and control the effects of an external expander via MIDI. The possibilities are huge.
The analog-like step-sequencer made me buy two (one for the note, one for the filter).
I got one as soon as it came out, but sold it because I didn't know much about MIDI. It was only later that I realized the possibilities the unit offered and bought two of them. There's no other unit on the market that can do so much for so little money.
Excellent value for money secondhand, but take your time to actually understand it.
It has a BPM counter that can be MIDI-synced, step-adjusted or Tapped.
You can control it with a MIDI controller (which I haven tested yet).
Effects are digital.
Connection options are pretty poor. Only one RCA audio input and output to connect it to a mixer's insert. MIDI IN/OUT. (no Thru...)
It's not rack-mountable but given that's it's more live-oriented...
I have seen some pretty complicated Roland gear, but this one is really easy.
Only one effect per effect (I don't know if you know what I mean....?) and it's a real pity.
The manual is relatively clear, but given its simplicity, there's no need for more!
Overall, effects are effective and worthy of good old Roland machines. I use it mainly live with a Korg groove.
I'm very pleased with the Ring Mod, as well as the Filter, thanks to the 16 sliding buttons that allow you to sequence the movements of one of the 3 parameters of an effect, which allows you to have a sort of arpeggiator live.
To me, the Synth Rhythm is absolutely useless, because it has only one single sound bank.
I've been using it for two months only and I haven't really looked into all the possibilities this machine has to offer, like preset programming, for instance.
But I can already have a blast making pseudo-melodies on top of sounds or very nice filtered transitions.
I also like the possibility to play along the entire pattern (between 1 and 16) and the subdivisions (from sixteenth notes to dotted notes).
I'm no expert on this type of units. I prefer PC plug-ins: More possibilities, more flexibility....more...more...LOL
I wanted to get a simple effects unit, adjustable live and for a reasonable price. And I found it! I got it for 220 euros in very good condition.