Did some listening today. 
System used: 
speakers - Audio Nirvana 15" in OB
amp - custom, 300B monoblocks (16wpc)
DAC/pre:  Isabellina HPA (RWA) & Maverick DAC on tour
source: iPod/ Onkyo Transporter (Wadia alike)
Keep in mind, unit is fresh out of the box. 
• gain: a bit high but not a major problem
• stock tube is OK but you can do a lot better 
• a bit edgy on the top
• missing some bloom in the middle range
• bass is not as refine and as tuneful as I would like
• image is somewhat smeared 
• it doesn't sound like $200 DAC 
• compared directly to $2500 DAC with similar features
is it a keeper? Absolutely.  
I am sure that with a bit more time and new tubes 
Maverick can compete with far more expensive DACs. 
Not exactly sure how profound and worthwhile those modifications are 
which can be found on Head-fi forum but it sure makes me wonder.  

So far, a wonderful DAC at basement price and great/useful features.  

I'll try its headphone section and analog tomorrow,
after that it is ready for NJ tour. 
 
 Cheers
Mariusz