Pass Labs X1 vs. XP-10

I am looking to get one of these to go with my First Watt F5. Curious if anyone has heard both and cares to render thoughts on the two compared to each other. I have heard the X1 is more transparent, the XP more smooth and rich. Is this accurate? Is the X1 more detailed?
I have read the posts on this forum and can't find much to compare these two.
A friend brought over his xp10 and compared it to my x1 a couple of weeks ago. The xp10 has a bit more detail, sound is more transparent and has lower background noise. The x1 is a bit warmer sounding.

The differences are not night and day but I preferred the xp10 over the x1 in my system.
I currently own a XP 10 and had an X1 in system for extended period of time. Buy the XP 10 it is a much better pre-amp. The XP 10 has a way lower noise floor, it has better highs, the mid-range is much more smooth, and the Bass is tighter deeper and way faster. The XP 10 is way more transparent in my system. I was going to buy a refurb X1 from Reno HiFi for a lot less money than a XP 10 but I was able to try both pre amps at the same time. The X1 barrowed from a friend and trial on a XP 10 from Reno Hifi and it was very apparent which one was better. I bought the XP-10. I will upgrade to the XP-20 in the next year.
I owned the Aleph P, the X1 and now the XP-20. The X1 was considerably more neutral and detailed than the Aleph P, though I loved the ergonomics of the P and the remote. The separate X1 PS also lowered the noise floor. The XP-20, though much more expensive, simply disappears. It is highly resolving of detail and nuance. It is very quiet. It is also very smooth without being soft. The sound can be "rich" if the recording is, but this is not a coloration or character trait of the preamp. I did listen to the XP-10 briefly in my system when I had the XP-20, but not for a long enough time to make an accurate assessment. After a brief A-B-A, the difference to my ears was small. More time might reveal greater differences.

If it were me, I would buy the XP-10. Of course, Pass suggests the XP-10 sounds better than the former flagship three box X0.2. You could try contacting Mark at RENO HIFI or Kent at Pass. They both know these products as well as the FW F5 and could give you another opinion. Depending on your system, you could also ask them about the FirstWatt B1 passive buffer.
I have not heard the XP-10 but if you can justify the cost, buy the XP-10. If you feel the cost does not justify the improvement, go with the X1. The X1 is a great preamp for the money. You would be hardpressed to find one better for the cost of a used X1. Pass made this pre for a long time so I would say they did something right with it. I am sure the XP-10 is better or they would still be offering the X1. On my budget, the X1 may be my last preamp.
Oh, I forgot one thing, I was reading that not too long ago, Nelson Pass was still using the X1 with the First Watt amps at the electronic shows. If you do some research online, it is not difficult to find this info.
i've owned an Aleph P and currently have the X1. recently listened to the X20 and really liked it. agree with the comments regarding slightly more detail (when the recording allows. i noticed this more on hi-res dvd's). also agree that it seemed a tad bit smoother up high as well. great pre-amp, but well out of my price range. i would have the guess the X10 is also a step in the right direction from the X1, but have never auditioned it myself.

Tzh21y is spot on regarding value imho. you'd be hard pressed trying to find a "better" pre-amp for the money spent on the X1. (used of course). i'll be staying with the X1 for a while. at least until i can budget a pre-owned X20. =)