Deferred disposition means that the disposition (end handling) of the case is being deferred )(set off to the future) while you do whatever it is that the court wants you to do. If you finish the agreed terms, then the case is dismissed - never prosecuted.
With a deferred adjudication, you enter a guilty plea but the court defers (sets off to the future) the finding of guilt and then do the terms you agree upon. If you do the terms, then you are never found guilty of the offense, although it is on your record because it was prosecuted.
Deferred disposition is always the better way to go because a case that was successfully ended after this type of disposition can be expunged off your record.
It would be advisable to consult an experienced criminal defense attorney in your area. Arrests and convictions can be reported many different ways and there may be a significant delay in reporting Arrests, Prosecutor Activity and Court Activity to DPS. Further, an attorney can fully advise you of the consequences of certain deferral programs and convictions on your ability to expunge your record, and of the collateral repercussions of the programs.