I've transited on a TUN-JED-BKK-JED-TUN in SV J in December and have another to KUL in a few weeks. Both overnight transits through JED was seemless and no change of terminals. Both arrivals were at evening quiet times. The terminal is big so a nice long walk off the aircraft to stretch my legs, very few people about. Then very quick through a security check before an escalator ride up to the departures area (shops, cafes, airport hotel, lounges). So from that aspect is was perfectly OK.

For me the worst part is the SV lounge:

• very cold (air-conditioning unit on full-throttle) and I had merino wool jumper/baseball cap/thick socks on, I had to give up and went to the gates many hours early as it's warmer than in the lounge - and no I was not ill with a fever.
• there was non-stop background music (not particularly low volume) which plays a short track over and over (inescapable acoustic torture). even the ear buds could not fully block it out.
• the "sleeps pods" are a few little partioned off areas (no doors) and their lights cannot be dimmed/switched off, so no chance of sleeping.
• the best place to sleep is the TV room, 6-8 comfy reclining chairs. the "warmest" room in the lounge (unless you're under the AC vent) and with the lowest light level - but you cannot escape the background music as the big TV was endlessly repeating adverts. On my second transit I parked myself there for the overnight and tried to sleep but not a chance.
• in the male toilets there was two showers but on both transits one was always out of action. You have to find an attendant in a light blue polo shirt for a towel/shampoo etc (SV staff don't help)
• the food is OK and but not much choice, nor with drinks. But a cook will put together pasta/egg dishes for you, so that was nice.

I judge the airport hotel too expensive for the 6-9 hours of my transits. So I'm not looking forward to that SV lounge for my KUL trip two 6-9 hour layovers, but it'll be the last time. But that's my experiences and others might not have the same issues as me. However, in the sky the SV crew were very nice.