I think the only difference is the LED, but not too sure for definate, you could email Gardner if you want to know for sure, I've only had the underlit so I think it's preference, I would definately advise on the deluxe receiver though,
Sometimes the underlit can be hard to see in the daylight if you just get a single beep(good at night though) , and the single led to the side might actually be more visible in that situation but I tend to look at the receiver if I can't tell.