Can anyone help me to decide which pre-amp is better ?

I owned a CAT for many years before resigning myself to solid state. It was a fantastic preamp. I upgraded from the original signature to MK II and later MK III. All 3 versions were wonderful. I also owned an Audible Illusions Model 3. A good preamp but not in the same league as the CAT. The CAT is not the last word in its resolution of detail but it throws a huge soundstage (blows away my current Spectral DMC20 II) and is wonderfully musical.

I have a BAT VK-5i and Just Love it. It was MY 1st Venture into the Treaky Tube World, Money Well Spent. I Can't speak about the others, I Haven't Heard them, but the BAT is a Class A (Legendary) Pre-Amp. I got mine on AUDIOGON at a Good $. The VK-5i CAN be upgraded to the 50se Level for about $ 2000.00. The VK50se is 1 of the Best Pre-amp available. Try doing some side-by-side Comparisons (use your EARS and the Specs). Good Luck!

To the BAT VK-5i fans: were some of them available with a built in phono stage? Thanks.

Lots of good suggestion here. You might also want to consider one of the new Sonic Frontiers Special Edition units, particularly Line 2 or Line 3. Very high value for the money, terrific sound, and good ergonimics with remote control.

The vk-5i and vk-50(SE) do not have optional phono boards. You must buy an outboard unit such as bat's p5 or p10.
The vk-3i and vk-30(SE) do.

The vk-5i has a fairly different sonics to the 50SE. They both have the bat 'house sound' which is a gloriously warm midrange, feathery well defined high notes, and excellent bass. Also, to paraphrase J Scull, the music has a 'breathing' quality. The 50SE is more transparent and revealing. The 5i has a little more of a 'glow' or vintage tube sound to it. I do run NOS tubes. One of the unique characteristics of bat tube equipment is that it produces extended high notes, yet remains warm and listenable. SS preamps can be a little 'too accurate' when playing high notes.