Upgrade DAC from AMR DP777SE

I have been using an AMR DP-777SE DAC which is now having intermittent reliability issues. I'm considering replacing/upgrading to either a
1) Chord Dave
2) PS Audio Direct Stream or
3) APL DSD ($$)

I need to buy used, and I'm comfortable with that. My hopes are for reliability, deeper soundstaging, timbre distinctions (ie violin & viola) and, most importantly, emotional engagement. I'm now 70, so my hearing ain't what it used to be.

I realize that responders are expressing their opinions, and my system synergy & sound room acoustics impact everything. I'm only looking for a DAC. I do hope to hear from you. Thanks from Olympia, WA USA

Current second system: flac & hi rez files→ APL DP-777SE→ Pass Labs XP20→ Pass Labs XA100.5's→ Ridge Street Audio Design Sason speakers. Cabling is all Jena Labs.
Thanks soix, I have never listened to or compared r2r DAC's. With this friggin'plague, it's not as easy as it used to be. Thanks 
I own the standard version of the DP777. Unlike you I have had no reliability issues but my two analogue rigs (see my profile) blow away the SQ I am getting with an Aurender N100H via WW Starlight Platinum 7 to the DAC. I ordered an SW1X DAC 2 Special with USB a month ago. When it arrives and I have had a chance to burn it in and listen, I will report back. 
Thanks fsonicsmith,
I'll be curious to hear back from you. Have you had a chance to compare your 777 to
1) Chord Dave or
2) PS Audio Direct Stream or
3) APL DSD ($$) ?
I certainly enjoy the sound of the 777SE, but intermittent problems are making me a tad crazy.
I also have the same with no issues.  I'm simply following as I'd like to upgrade as well.

i second soix's recommendation on r2r dacs - there are many very good ones out there for a fraction of the cost of a used chord dave