Is HDMI worth It in term of sound quality?

Keep what you've got. HDMI is a convenience only. Going from what you have to the Pioneer will be a huge step down.

You can still take advantage of the same uncompressed audio as with HDMI provided your source can decode the new formats and have analog audio outs to your preamp. I "down graded" from an HDMI equipped low/mid level Onkyo TX-SR705 receiver to a flagship NAD T773 receiver with no HDMI. I use my Oppos multichannel audio outs to the NAD's multichannel audio ins and let the Oppo decode the new HD audio formats. I initially switched to the NAD because I wanted a flagship receiver with better overall sound when playing music. Not as convenient as HDMI but the NAD is just a better built, better sounding piece of gear than the low/mid level Onkyo.

On the flip side, the Pioneer receiver you are interested in is of very high quality(as today's receivers go) and does have just about all the modern conveniences available today.

Bill

I disagree to get 1080p you need hdmi. But most of the sources are not 1080p anyhow. It a toss up and what you need out of the system.