Well, I've been. And come back.
I missed the Plassey, but we heard plenty of Gaelic, and the place did have a faint aura of Father Ted. The subject of Father Ted came up on the way back to Banagher, as we went through a town that had very mildly rude words spray-painted on the road signs. "Knickers", said one; "Arse" was another.
We pictured a party of tipsy priests coming home from the pub, daringly writing the rudest words they could think of.
To be honest, there isn't much to see - most of the reccommended "sights" are ruins of one kind and another - apart from the seal colony (which contained no visible seals when we got there. No worries - we've seen seals aplenty elsewhere). As a place to just pootle around and chill out, but with some good pubs, good food and good craic, I'll reccommend it.
Forget the campsite. €10 per person per night for a field and some rather grotty loos is way too much. I would guess other accommodation is similarly pricey. Find a discrete spot away from the villages by the sea and pitch your tent there; just take your own loo roll and a trowel.
There isn't much traffic, as there aren't many roads. What You Do is to hire a bike as soon as you step off the ferry (assuming you haven't brought your own) and Do The Ring of Aran. So on an Irish bank holiday weekend, the place is full of people on bikes, wobbling rather erratically around in the wrong gear, stopping and turning across the road without warning, and not being sure which side of the road it's best to be on (lots of continentals there). All good fun.
The only motor traffic is the mini buses which career around the island at top speed, fetching visitors and their luggage to and from their B&Bs from the ferry. The quicker they do this, the more trips per ferry-load they can fit in, obviously. And when that's done, they do whistle-stop bus tours of the island.
Fortunately, most visitors' response to any approaching vehicle is to stop and get off the road. Given the standard of minibus driving, and the average level of bike control, that's probably just as well....
Anyway, here's some pics to get you drooling:
Oh yes, and guess what these whacky French people are doing: