The First Street Lounge (actually located on First Street in Sanford's Historic District and not Debary) is a relatively small establishment and serves beer/wine only 4 days a week (Wed.-Sat). Karaoke is on Wed. & Fri. Nights and they have a Cabaret Show on Saturday Night.
Karaoke there is typically not good. You have a handful of good singers but a lot of it can be pretty awful. Same singers and songs twice a week.
The Cabaret Show can be repetitive from week to week. The Emcee tells the same jokes, and the show tends to drag (no pun intended) on way too long due to excess joke telling and bantering by the Emcee.
Probably the most critical thing I can tell you about The First Street Lounge is that they don't have the typical "Happy Hour" or "Drink Specials" that most bars have.
In summary, there's really not a whole lot of reasons to choose this place over the many choices you have in Sanford and the surrounding areas.