Bearing in mind the low cost fares the basic lounges provide a comfortable place to wait, surprisingly good free WIFI (login codes distributed at lounge front desk), ample electrical hookups, free tea, coffee, juice, basic sandwiches and muffins.
Its not luxury but lot better than waiting in the public areas. The basic domestic lounge at BKK I would rate higher than the international.
Outstation lounges are variable but still offered to all passengers.
The basic domestic lounge is indeed better than the international one.
The lounge at Chiang Mai is abysmal but the ones on Koh Samui are very good, especially the Blue Ribbon.