db2265, first of all, welcome to the site. Both are good scopes and both have advantages and disadvantages.

The red dot is a little more compact, but not usually very might lighter in weight (depends on which scope you choose). The red dots have no magnification so for areas that require that, they are great. The down fall is the battery, they always seem to die at the most inopportune time.

The scope usually has some magnification to it. This will help in it's light gathering ability in the lower light conditions that we sometimes find ourselves in. Also with the Excalibur Varizone (and the new model with lighted reticals), there is a SPEED RING that if you know the speed of the arrow, you can switch from one weight or arrow/head to another and only need to adjust the speed ring to keep your scope sighted in (only needed to be sighted in t start with). Also you do not need a chronograph to figure out the speed, the scope can help you do that.

Me personally, if I was getting an EXOMAX, I would go with the Excalibur scopes just beasue they give me much more options which keeping it simple (no worries about batteries).

Good luck.