A friend of mine from Lviv tells me that Ukrainian language is closer in structure and vocabulary to Polish than to Russian. I can't really assess this information, as I speak only Polish, from these three.
That's right, but only few people speak pure Ukranian language (and they do it mainly for political reasons). It is incovinient as it lacks some modern words and concepts. One can discuss prices on the market or neighbor girl, but when topic is switched to scientific or ingeneering matter - Russian is language of choise. Same with Kazakh language - the language of nomads.
Confirm: Ukrainian is perceived by russians as "peasant's" language. As for scientific and engineering matter - I observe more use of words borrowed from English.