Preamps with variable gain... pros and cons?

I am considering a preamp upgrage and have noticed many high end units have adjustable gain (in addition of course to the volume control). What are the benifits of this feature? What units have you auditioned or owned? What models would you recommend? Is this soley a solid state feature or do any tube preamps have it?

Many thanks.
On the Rowland Synergy IIi, increasing the gain and decreasing the output volume by a similar amount causes a noticwable improvement in dynamics.
the best budget preamp in that issue is mccormack micro line drive that has three active modes of operation 0dB, 6dB and 12 dB of gain and completely passive where you can use it with no power supply.

i did not research a tube preamps on that issue but everything is possible there since even for small signals you can use switchable to tetrode operation thus increasing the gain or decreasing back to triode...
For years I used a Pass Aleph P which has this feature. The idea behind it is to optimize your system's gain structure. The preamp sounded best when the gain was high and the volume control attenuated least. The feature is not absolutely necessary, but it does allow for a level of added refinement.
My whole audiophile life has been spent with systems where the preamp volume is rarely above 10:00 and where sometimes I can't turn it down enough. I'd like to see more of this kind of adjustment, as well as selectable output from digital sources, many of which simply have too much gain.
Thanks guys,

I will check out Rowland, Pass and McCormack.
somehow i recalled that that BAT VK50 tube preamp have an adjustable gain that is very simple to set up simply from the front panel from the attenuation levels to the higher amplification levels using 24 steps attenuaters on each of the channels(i assume that this preamp is dual-mono).
The pass labs x1 can set hi OR Lo mode gain on a per-input basis. A great feature.
The pass labs aleph P has per channel variable gain as does the BAT vk-5i. I found that the BAT sounded best with the gain set to MAX. Brought out the tube sound the most. The aleph P sounded best with the gain set to around 11 oclock. The feature is quite useful - especially since different people have different tastes. Some like the transparency of a more passive pre, some like more dynamic drive.
I have a tubed Supratek Syrah pre and also prefer it at max gain. It has 5 different gain settings so you can try different settings to work with your amp. I have a few cd's that seem to have been recorded on the lean or bright side and lowering the gain (and raising the volume) helps.

I have an Audio Research LS 25. It has gain adjustable in 3 increments - 6dB, 12 dB, and 18dB. This works great for me because the 12 dB setting is perfect for cd, while the 18 dB setting is great with phono.
Gain controls are useful for channel balance adjustment. Atma-Sphere tube preamps have this feature.
The Rogue 99 also has the gain control. I find it useful with the remote feature because I have finer volume control at lower gain. The differences in quality at different gains are very small.