Amp for Benchmark DAC1 Pre?

Hi i'm a newbie who just purchased a pair of Usher Be 718's and looking for an amp.

I was looking at the Musical Fidelity A5, and then though about getting a DAC. But fellow Audiogoners have recommended the Benchmark DAC1 Pre.

Anyone familiar with the Dac1 Pre? Is it about as good as the MF A5 or a level or two lower?

I'm still trying to decide whether to get the MF A5 and a DAC or the Dac1 Pre with an Amp.

BTW, which imparts more to the sound-- the amp or preamp?

For the AMP:
1. Ushers are hard to drive, need at least 150 watts
2. Benchmark pre has no added effects, such an amp that would add a tube like quality would be very welcome.
3. Something that would give me something similar in sound to the MF A5
4. Budget conscious: preferably no more than $800 here on audiogon
5. Want great musicality, tube like sound, great bang for he buck sound that nearly equals a 7-10K setup.
6. If possible one that may be a little more forgiving to bad recordings (not a first priority, but if possible).

Rest of my system:
will buy the new oppo blu ray player to use as a CD player along with a DAC
cables are "budget audiophile"
intend to do a lot of squeezebox listening (rhapsody, internet radio, pandora)

Thanks!!