Anyone own one of these preamps ?

I use the Benchmark LA4.  It is totally transparent, if your system is at all bright this is not good, but if you are looking for resolution, spatial awareness and neutrality you cannot do better.  If you want "soul" look elsewhere.

It has two RCA and two balanced XLR inputs, single RCA and XLTR out, plus a mono XLR.

Volume is controlled by relays and precision resistors.  The remote will control volume and input selection.

The reviews of this component are accurate.

A thought, in your price range, is the Cary SLP-98.

these are units that more or less intrigued him in one way or another over the past 5 or 10 years but as I said in the original post, he’ll need to determine synergies (or lack of) with the rest of his system.  

It still all comes down to what sound characteristics are most important to him and what specific improvements he’s looking for over what he has now, so again I ask what preamp is he using now and what specific improvements he’s looking for?  Frankly if he’s considering all those preamps it indicates to me he doesn’t know what he’s looking for because they’re mostly not substitutes at all as they’re so completely different. 

I don’t disagree with you, it’s like a mish-mosh of different kinds of sounds.    He can get his own Agon account lmaooo.    But his amp (Parasound A21+) is pretty solid IMO.   The Parasound P5 preamp is a weak spot, again IMO.   

I’ll just throw out the Spatial Audio Raven because it’s in his price range and will likely be a substantial across-the-board upgrade from the P5, and they offer a generous 45-day return period that’s a nice option to have.  There’s also the Backert Rhumba or Rhumba Extreme that also offer a return policy and very worth a look. 

I just want to support what @stevehardy1 said in his earlier post. The PS Audio PMG Signature preamp is wonderful and would be a great addition to your friend's list. This preamp is transparent, dynamic, sweet, and non-fatiguing, and there are many strong, positive reviews online.

It is an interesting connection to your friend's Parasound gear that Darren Myers, the engineer/designer of the PMG preamp, was lured away from PS Audio to Parasound after he designed the circuits for the PMG pre.