Roland UA-55 has how much better sound than UA-25EX had?

[darvaskristof]

I'm hesitating between to buy a used Roland (Edirol) UA-25EX or spend 2-3x more money for a new Roland UA-55.
Someone, who had experience with both of them, could please explain me UA-55 has how much better converters than UA-25EX had?

I know about the practical benefits of UA-55 (e.g. switching sample rate without unplug, full duplex 96 khz, auto level setting etc.), but what interests me is primarily the analogue output quality.