Same here. Macbook Pro and Audirvana+ (with Toneboosters TB Isone for half of the recordings when hearing trough headphones). Happy.

Jriver works fantastically and I have the Master License so I can use it on my Mac and windows machines. Jremote is an excellent remote.

Biggest things for me? R128 loudness analysis which allows for super consistent playback levels when jumping between different albums and genres. Classical and death metal can coexist without reaching for the volume knob. Also keeps things from playing back with intersample peaking.
Internal volume is also totally transparent.
And the standard crossfeed is always on if I'm listening to cans. As someone who prefers speakers, it is perfect and less fatiguing.

JRiver also has a very good message board you can check out. If you request a feature and it makes sense they will implement it; same with bug reports. Their audio core is so mature at this point.
Foobar also has a ton of posting over on Hydrogen Audio.
I don't know if Foobar does all the zone stuff, internet radio streaming and recording etc...

R128 loudness analysis? Now I want to try JRiver.

None (overflow flatline) - This mode will protect against clipping (sound values getting too high resulting in bad sound) by hard limiting the values to the maximum allowable level (100%). When the peak level begins to exceed 100% by too much, this method will sound distorted

Clip Protection- Clip Protection mode protects against clipping (sound values getting too high resulting in bad sound) by scaling the volume to keep the peak level at or below 100%. This method will prevent any distortion

Since all audio data is 64bit floating point, there's no hard limit at -1.0 and 1.0.

So if one effect does +100dB and the next effect does -100dB, no clipping occurs.

It's only a clip when that hard-limit between -1.0 and 1.0 is enforced before output (because it's required by the soundcard), and this is only at the very end.

So I think the current behavior is desirable and correct.

Source:
JRiver Wiki:

http://wiki.jriver.com/index.php/Category:Frequently_Asked_Questions

I personally use Clip Protection. It will never allow sound values getting too high resulting in distortion - which can happen if you use None (overflow flatline). But I also use iZotope Ozone 5 EQ and sometimes iZotope Ozone 6 EQ plug-ins for eq'ing, they too have auto-clip protection thus I never have any clipping or distorting.

Another option is to use Volume Leveling in the DSP studio options. It uses the R128 algorithm to analyze files and apply the correct playback volume for every song thus preventing you from ever having to mess with the volume control as all songs will be played at the same volume, while preserving intentional volume differences between tracks on the same album.

So I think the best option is Clip protection, which is what I use. When you use overflow flatline you can get clipping and distortion when the peak level begins to exceed 100% by too much. Since albums are mastered at different "Loudness" levels (some albums (CD's) are mastered at 86db, and I have seen some as high as 97-97db). As someone who records and masters my own music, I am very familiar with these concepts (LFF also has much more knowledge than me when it comes to mastering and clipping, but not sure if he uses JRiver, but he can tell you a lot about those concepts, he is much more knowledgeable than me).

You always have the freedom to try both, but if you choose overflow flatline and experience distortion or sound volumes getting too high, then switch to Clip Protection - I found that is the best option for me - and you may want to consider what I mentioned above and use the Volume Leveling option in the DSP Studio options of JRiver. That along with Clip Protection is probably your best bet IMO. I personally do not use Volume Leveling, but I think I am going to start so I can set the volume on my amp once, and all of my songs, regardless of how loud or soft they are mastered, always play at the same volume. So that is my personal opinion. You can try these suggestions and find what is best for you. JRiver is incredibly versatile and powerful!

You're most welcome!