Ok, First let me say that after I got the 551, I thought it just didn't sound nearly as "Vinyl" as any of my vintage rigs. It had more detail and "presence", that I liked, but just too CD sounding. Well, during all of the preamp changes, I upgraded my phono cart, and this went a long way toward a warmer vinyl sound. But as verified by hooking up any of my vintage receiver preamps by using the pre out leads it wasn't nearly as warm and lacked low end. I realize some of this may have been coming from other parts of the vintage gear coming through the pre outs. But I still wasn't where I wanted to be. So I went to the 651, it was just a little warmer, and a little more detailed than the 551. Let me say that all of these preamps sounded very very good, I just didn't think they were letting the full performance of the rest of the rig show. Then came the Pro-Ject, I tried hard to like this one because I liked the different settings, but none of them got me where I wanted to be. The Pro-Ject was much warmer and had more bottom end than either Cambridge, but lacked that high end detail the Cambridge 651 had. Then I thought, "One more try". Kinda of a swing to the wind, I got the NAD pp2. I found the pp2 to have the warmth of the project, and the detail of the Cambridge 651. And I thought about staying with it. Actually I just happened to have a little extra money from some OT I've been working, so I said to myself. I just want to see why the Rega won preamp of the year 2 years strait according to What Hi-Fi. I too take their recommendations with a grain of salt, but I thought I would go ahead and try it, and send it back if I don't hear a definite improvement. Well, I just got the Rega today and was immediately able to tell the difference. It has more low end than any of the others, is warmer, and just as detailed as the 651, if not more so. But the real difference is in the sound stage. The rega is deeper, wider, and has a much more detailed sense of space. Like a live performance. I wholeheartedly recommend it if it's within your budget. I rank the rest like this, from worst to best. Cambridge 551, Pro-Ject phono box, Cambridge 651 and finally the NAD pp2. Actually the NAD is the one I would recommend if you don't want to go the $395 for the fono. But really none of them are bad, there all actually very good, the Rega just seems to be in another league IMHO.