Hi to threadstarter,
you've to decide on several things in order to discern which or what delay is for you,
1. what do you need the delay for? what kind of music do you play?
2. Preference between analog and digital, but it mainly stems from the first consideration.
Some people just need a warm, simple delay for that added texture. Then you'd go for a nice and simple analog delay.
Some people prefer creating whacked out tunes, say experimental music, then it'd be better to go for something multi-functional like a DD-20 or DL4. Both of which have many varying and interesting delays for a musician to experiment with.
A DD-3, DE-7, AD-9 would fall under the simple delay category.
Then there's the point of digital and analog, as mentioned earlier. Digital gives you exact replications. It's clinical and precise.
Analog delays are muddier, and thus the 'warm' description.
Both has it's advantages, and both are useful. So ultimately, it depends on what you need.