Clear, fairly neutral without bass boost or stereo enhancement on, can drive most phones decent, but you may want a more powerful amp for large ,hard to drive home phones.
Really from portable to portable amps in comparison from $100-$250, there isnt a MAJOR difference anyway.
There are differences , but dont expect them to be totally different on every headphone. Sometimes you have to listen for differences a bit.
Sometimes people totally exagerate the differences between amps etc.
For $109, its a nice amp, well built, small, cute, good features, rechargeable, lasts over 70 something hours on a charge in most cases.
Sometimes i notice differences between all my portable amps,, and on some songs with some phones, its hard to tell.
Really i can babble on and on, and you can also listen to everyone elses babble and bullcrap, and learn absolutely nothing about anything on this forum until you listen for yourself.
Someone will say they think an amp sounds one way, and ill disagree totally.
Look at the Allesandro's. Some people say theyre warmer, some say they got more highs. People cant agree. Its freeking rediculous. They either have more highs than Grado's, or they dont!!!
All i can say is, try it. I like the amp for the price. Its not the be all end all, and its not super ultra special or anything, but it does the job, and its a quality amp for the money that id recommend and not be embarrassed by, and im sure many people would buy it, be happy enough, and stop right there.