As you say, Duaplex, some of the very said players function with no problems what-so-ever and others just fail.
My BDP 450 loads and runs with no issues, apart from the Network side as I mentioned before. That however is not a great issue as many amps these days duplicate the same features via DNLA anyway.
It no doubt sounds you got a duff player. Sorry for that. Had it been a Sony or Panny with the same faults, it wouldn't then mean they're all bad.
I too would always recommend buyers go for the popular recommendations if they match their budget and purpose.
I went for the 450 because it filled both for me. The Panny DT500 and Sony 790 too are excellent players.
I hope we all comfort in whatever we chose.
Kit : Yamaha RX-V673, Q Acoustics 2050i, Pioneer BDP 450, Chord Silvern Screen Cable.
I went for a demo of the BDT500 and S790. Honestly, I did not think much of the Sony. The BDT500 displayed more detail, and handled motion better, in fact it was very close to the performance of the 751BD which I also tested.
I will certainly give this pioneer a go that you mention on my next trip.
The LX54 unfortunately is not faulty, it's a common problem experienced by many. Clearly it must be more to do with hardware than software, as you have clarified yours is more responsive.
My Cinema Room
i have both, I meet an issue on the BDP-450 a shift between screen and the sound when I use the ' separate' mode:
I plug the MAIN to my TV ( kdh46hx850) and the SUB to my Yam Rxa3010 in full HDMI mode of course.
the screen is arriving a little bit before the sound, so I can not use the delay function , because just add a 'add' shift.
but the sound seems clearer whe I use the separate mode,
the bdps790 seems have a screen with more contaste and the coulor more deep ( brown / blu).