It's a mixed bag. It's not near the quality of studio grade effects processors like my Ensoniq DP/2 or Boss VF1, but that's not what it was really made for. You have to tweak certain effects to get the best sound, and certain effects are better than others. There is a certain lofi element to this, which is fine for the harsh type of cyberpunk music I make. The filter is pretty good...I don't understand why some complained of stepping, maybe lower cutoff settings are more noticeable...my theory is they either had a bum unit or were using it wrong IE: they must've had the bpm sync on while twisting the cutoff. Every digital filter I've used steps, this one's no different, but it's no worse than you'd expect. It does step noticably when you try to tweak the filter while the synth is running...this is most likely due to Roland skimping on the DSP power, the processor chip just can't cope. Manufacturers need to start using better DSP, in this day and age, there's no excuse for that kind of cost cutting. If Alesis can do it with the ION, anybody should be able to.
Anyways, throwing the filter into sequence mode is where it gets really fun, instant drum damage....you can even select SMOOTHING so that your sequence steps aren't so "steppy". Certain effects work better with the step sequencing than others...for some reason, I can't get the reverb to do anything with the stepper, but it's a pretty decent sounding reverb. Isolator does what it's supposed to, but this one I also can't get to do much with the seq. Flanger is okay, better when sequenced, the Phaser is better. Delay/Pan and Pitch/Delay are excellent, the delays are one of the best things about it. Slicer/Pan is good for those rhythmic gating effects without having to go to the trouble of setting up a gate with a sidechain. Compression is pretty good, I've gotten strangely dynamic, pumping phrases by using the seq with it. Flanger is kinda weak, better when sequenced. Phaser is decent. Lofi is good in small amounts, a very digital sounding bitcrusher/distortion. Ring Mod is so-so, keep the wetness down. Voice is really good, not the VT1, but as close as you can get without buying one. Vocoder I haven't explored fully, but using the internal synth, it's good for drum destruction. Syn+Delay is ho-hum, a little too FruityLoops Synth sounding for me. Syn Bass is much better, as the dsp has less to do...it's as good as most software emulators like Rebirth, BETTER because you have the real 303 interface, no mouse clicking. Syn Rhythym is fun, but more of a bonus. Sounds like a cross between a TR606 and CR76 or something...won't replace a drum machine, but it's fun and somewhat useful.
You can select eq ranges to effect, which is very cool especially with delay settings, but unfortunately you can't isolate 2 bands at once, it's either hi, mid, lo, or all.
According to the manual, you can use the EF303 as a CC Box to control external gear, but I haven't tried this yet, it's easier to use my midi controller.
I'd depend on it. It's really solid, sturdy sliders/knobs, steel chassis. I've had it about 3 years so far, bought it used.
There's a few flaws with the EF303...the aforementioned grab switch quirk, the RCA ins/outs instead of 1/4 TRS, Tap Tempo is kinda sketchy and slow (don't believe the hype, Roland still can't get this one right on their current gear like the 909...the cheapo Zoom ST224 did tap tempo way better). There is no SPDIF no digital in/out...perhaps the biggest "GOTCHA" is that the 303 sequencer doesn't transmit midi...that's right, you can't use the sequencer on your external synths, no glides, no accents, nada....obviously Roland wanted you to go out and buy the real thing, I don't know. There's no way I would've paid what these things cost new, but at the use prices now, it's hard to complain about it. If I lost mine, I would definitely try to find another one, or something similar, like the Adrenalinn.
If you're sick of clicking around on a computer screen or paging around rack effects, pick one of these units up for $150 or less. If it doesn't make your music-making process fun again, I'll buy it from you. Then I can have step effects into more step effects! Moihahaha! I wish they had digital connections, so I could have several of them in a big circle, Max Rebo style. Tell me that wouldn't own. In my opinion, the EF303 was a brilliant concept that wasn't as sucessful as it should've been...much like the Alesis MODFX line, another brilliant product that should've been a hit. For people who work like I do, these are great hardware units to have around.