My 5400 was better than my 777. If you want Blu Ray get an Oppo 103 or 105
First of all, you have a great player and if you like the sound of it, stick to it. Second and in terms of audio, there possibly a wide range of what's you gonna like more, but it may be not. The universal players like OPPO mostly are used with external high-end DACs, they do cost a lot. So if you really want to get rid of your SACD and to start that looooong listening session in search of your sound, then the marked is wide open. But I haven't seen high-end BR players with an outstanding DACs combined.
I have a top of the line Sony Blu-ray player and also the 777. I do not notice a difference in CD/SACD media play back from either as compared to the blu-ray player. So, for now do not sell off the 777. I have not heard the Oppo 105. I think if any blu ray player could best the 777, that would be the one. Since you can get a 30 day return on the Oppo 105, I would suggest you do an in house compare. The ears will tell.
I have a 9 year old parts connexion modded Shanling T-200 CD player and just sold my new 7 month old 5400ES. On Sony, bass was a little better and a smidgen more detail but Shanling was more musical and analog sounding. And looks better. The heavy aluminum frame on Shanling probably helps block out RFI. Plus it looks way cool.
I have both 777es and oppo 95. The 777 taks minutes to load sacd. The 95 has fan which is annoying. For two channnel, the 777 is good and oppo is better. For multi-channel, the oop is much capable. The oppo can also play my sacd backup in iso format. Never heard scd5400. In my music listening experience, the most import is the music itself and recording. The pursuing of perfection of equipment will never end and not necessary.
I was in the same dilemma awhile back....and decided to hold tight...ES players are fairly well regarded...especially older players...unless it konks out...keep it....not missing much at the moment....most of the improvement has been on the computer driven side of audio...downloads, streaming, etc....SACD vs DVD-A was over a decade ago...and Blu-ray is a video driven medium...concerts, etc......