Any suggestions on Tube Buffers?

I have an Onkyo P-308 M-508 amp/preamp combo that I'm quite pleased with but am curious to wet my feet in the world of tubes. Anyone have any experience with this? I was thinking about a Grant Fidelity M-283 tube buffer between the amp and preamp. I know it's not a full blown tube setup but maybe it will give me a little taste of the magic. I really don't want to have to take out a second mortgage. I will be driving Polk SDA-1B speakers. Any suggestions would be appreciated.
I've been curious about and researching the same thing. I believe from what I've read that the GF M-283 is the same unit, but priced higher than the Yaqin CD2 buffer. You might want to try the CD1 which is the high end version of the CD2. It can be found brand new on ebay for about $125.

Give us the update if you decide to try one out!

I saw the 283 on their site for $125. Honestly though, all you are doing is "messing" with an already clean signal. Personally, I'd consider a tube pre instead to get a better taste of tubes. I don't think a buffer will give a real taste. It's simply going to softenwarm up the sound a little.

Save for a pre
I agree with above post. I owned an EE minimax BBA, arguably one of the better buffers out there. Inevitably you will be adding another component to the chain and purposely coloring the signal (or compensate for it, depending on how you want to look at it). In the end, I found the resulting sound was more veiled and bloated in the midrange. Removing the unit was akin to hearing what sounded like a 'purer' signal. If you want to wet your feet the right way, I suggest a reasonably priced tube preamp.