Get the Lexicon. I have a PCM80, Nuverb (Lex 300 on a Mac Nubus card), LXP15II, MPX500 and a Vortex, they all get used alot....I also have a DP4 that I never use...It just sounds thin compared to the Lexicons.
Ummm go for the DP , the lexicon MPX100 is very limited ( although the MPX1 is much better) , if your budget can stetch the lexicon 80 , 81 , 70 and 60 ( both second hand so quite cheap ) are much beter on the reverb front.
The main difference is that the Lexicon reverb sound integrates itself into the origional and sounds very lush whereas the Ensoniq layers itself over the origional and sounds more artificial.
Both are relevant in different production situations and you have to decide which sounds are more pertinent to your use.