Ubiquiti EdgeRouter Lite 3 port + switch?

I'm planning to replace my current single-unit router+AP with some kind of Ubiquiti Router + separate AP. I'm wondering if it makes more sense to get a EdgeRouter Lite (3 port) and connect one port to a larger gigabit switch, or if I should get something like the EdgeRouter X (5 port). Is there any practical downside to going with the first option?

Also, do these Ubiquiti products ever go on sale?