I mainly use the analog setting for general playing, its sounds more natural. for practice at home I like to use the hold feature to play a few chords and loop them. that way I can play solos along with the chords i strummed that it plays back.
You can do allot with this pedal, if you know how to use it correctly. its very versatile as far as the types of sounds you can use it for. you can get a reverb like sound, slap back for surf and rockabilly, crazy echo like sounds, guitar doubling type sounds or just fatten up the sound of your solos, you can get that chicken picking sound (a compressor and a delay really makes the chicken picking sound perfectly) and you can do all kinds of other stuff.
this a really good sounding pedal, the digital delay modes do sound digital but they still sound very good. I think the analog delay setting sounds allot more dark and natural. that is why i go the DD-7 over the DD-3, i wanted that analog setting. I had a DD-3 for quite a while and decided to upgrade to a DD-7 and I am glad i did. both are great pedals and most people would should be quite happy with either one.
I am not really a external pedal/effects person, a good tube amp should have a good overdrive and hopefully a good reverb and that is all you really need for most types of music, add a delay and a compressor and you have plenty of effects to play around with. having loads of pedals and effects is really just overkill for most types of music IMO but a few basic ones are nice to have.
when I play live I really just use the overdrive on my amp and when I play a solo I hit the delay and sometimes compressor to fatten up the sound, that is all I really need to play some rock and roll music, rockabilly or anything else.