Do you need a delay and/or reverb ? If so, then go for the DEP-5. If not, then go for the CE-20.
Personally, I would get a Boss VF-1 rather than either of these. They can be had for less money than the DEP-5, and only a little bit more than the CE-20 and are packed with the following 24-bit effects :
Chorus, Compression/Limiting, De-Essing, Delay, Distortion, Feedback, Graphic Equalisation, Harmonic Enhancement, High-Pass Filtering, Low-Pass Filtering, Noise Gating/Expansion, Overdrive, Parametric Equalisation, Pitch Shifting/Harmonizing, Reverb, Shelving/Gain Control, Simulation, Vocal Effects/Pitch Correction