A newbie to KTX - review and suggestions

Just completed a roundtrip from Cheonan-Asan to Mokpo on the much ballyhood KTX. So here's some of my impressions:

The trains were indeed clean, fast and comfortable. I noticed on the return trip that we reached 299 KPH (about 185 MPH for those of us that are metrically challenged, ha), as displayed on the TV screens. But that speed was somewhat short lived, I suppose that depends on factors such as track condition, traffic, curves, etc. Wait times at stops was very short, and the trains ran slightly ahead of schedule.

The Korail staff is exceedingly polite, patient and helpful.

The advertised Wi-Fi: it was a No-Fi for me on the return trip, after multiple tries and signals noted. Good thing I had magazines. Has it worked for other folks?

Tote some food and drink for the trip, as the light cart food on the train is expensive.

Oh, on those TVs: Programming is in Korean, and if you want to listen you have to buy (rent?) a headset from Korail. Not good news when I was carrying my new earbuds! From looking at the audio jacks on the armrests, one of those two pronged airline adapters MIGHT allow you to use your own gear. I'll try that on the next trip. The KTX magazine (some in English) indicated that movies are shown in car #1, not sure if there's a charge for the movies.

If you're in a large-ish group, the middle of our car had 8 facing seats and a table, so that is an idea for longer trips. And the even numbered rows offered the best window views. Sat in an odd row on the return trip and peered mostly at a bulkhead and the green curtains... blah!