Well, booed on the stage is something that every opposition leader experienced
Can't say that hurt Klitchko much
I still consider him to be the favorite of presidential race. He is respected in Eastern Ukraine, he have never held any position so he has no negative history and people do believe that guy who made millions using his fists has no intention to steal billions and build a palace for himself.
Many dislike that his team has many old faces, myself included. I'd much prefer if he did what Saakashvili did in Georgia - Mostly young specialists
Tymoshenko... One of popular jokes in Ukrainian Internet - "If Tymoshenko will become the new president, let's not destroy barricades because we gonna need them soon". She represents old Ukrainian politics with all "good" things it had.
You see, the whole situation in Ukraine is a compromise between revolutionaries and parliament: Knowing that legitimacy is needed and a random group of people from the streets can't make new laws, armed guys on the streets allow parliament to do what it is needed. But there are very little trust* toward that guys, we totally expect that they will play political games of the past with all corruption remaining in place. Returning to pre-Yanukovitch status quo is not enough at all
*Sometimes people are too paranoid if you ask me