Reporting back after trip: due to rainy season weather affecting original itinerary plans, I made some real-time adjustments once in Indonesia and ended up taking only two (2) domestic segments. Try as I did to take the above advice, it didn't work out that way due to itinerary and timing.

1) Surabaya-Makassar. Batavia Air, on a 737. Plane seemed in reasonably decent shape (well, I didn't hear any rattling!) and was on time departure and arrival. Though there seemed to be quite a few delays on other Batavia flights. Piloting skills and cabin crew conduct seemed also fine and very smooth. No scares here, that I could detect. I would consider flying Batavia again but only on jets not props and only on some routes.

2) Makassar-Jakarta. Sriwijaya Air, also on a 737. Garuda was an option but was double the cost and quite expensive in absolute terms. And I wanted a morning flight, which wasn't available on GA on the day I needed. It was ontime departure and arrival, however, I didn't like Sriwijaya and was very uneasy. During flight, cockpit door was forever opening and cockpit crew taking turns coming out and hobnobbing with the cabin crew. Or cabin crew were forever going back into the cockpit. For a lousy less-than-2-hour flight, what the heck gives? Didn't seem to be very professional to me. Which didn't give me confidence about all the airplane-related things I couldn't see. I wouldn't take this airline again regardless of cost savings. Something just didn't feel right about the set-up.

Unfortunately Mandala didn't fly in/out of Makassar so no options there. Lion Air had some options and fares were cheap but they had a lot of delays also, and I'd since heard a lot of scary stories about them. Air Asia local not an option on this trip.