Thanks - just figured it would get us out and stretch our legs/see the sun after a redeye from BKK. My bigger concern was it is worth the hassle with getting visas just for a 3 hour tour? We could just transit right to the lounge and veg out instead. Probably will just decide on the day depending on if we get any sleep on the first leg.
If you're eligible for the e-visa, I found that process relatively quick and painless. My understanding is that US, UK and some other passports can get a visa at the airport as well, if you prefer to decide when you get there, but I have no experience with that.