We used Bangkok Airways earlier this year to fly from BKK to Siem Reap & they fully deserve all the praise. We arrived on time from AMS our booked connection was in 7 hours as that was the only available flight when we booked, at the transfer desk we enquired if there was any earlier availability, we could get one in 3 hours no extra charge & whilst they rebooked the flight telephoned through to baggage to get the bags retagged.
On the return the flight had an inbound delay we were connecting to TG to fly to Krabi, once we got off the bus from the remote stand they had people there to escort you through VIP immigration, to the baggage reclaim, they phoned TG to say we were on our way & wanted to escorted us from international to domestic terminals. As we knew were to go we thanked them & went on our own. When we got to the TG check in they were waiting for us.
Very hard to beat that service level.