Re: delay pedals: Boss DD-3 or Marshall EH-1
Since you're not getting much help here, I'll chime in with half of the answer. I've not played the Marshall, but I've owned several Boss DD-2s and DD-3s over the years. The Boss boxes are indestructible, and give a lot of delay time in a very compact package. They are clean and quiet.
If the DD-3 has a failing, it's that it is too clean. Many people think the delays are too bright, or too hi-fi, and prefer the funky, dirty sound of an analog or tape delay. When I switched from a DM-2 to a DD-2 back in the 80's, I noticed the brighter sound of the digital pedal. Sometimes, it is hard to dial in the wet/dry mix because the repeats cut through a little better than they should.
However, if you find the DD-3's repeats too bright, there is a simple one-component mod
that will fix it for you. I think the DD-3 is great, and recently bought a used one to add to my pedalboard.