infinitive vs preposition. It's good to meet you. <<< Meaning "meeting you" this action, event, deed, is good. It's good to meeting you. <<< Meaning "it", whatever the heck it stands for, is good for the event "(me) meeting you", although it doesn't make much practical sense, usually. Now get your grammar book and make your first contact with situations where "something is good to "meeting you" makes perfect sense, semantically, even in your native language thinking, eg, be used to an event/habit, where the event you're used to could be replaced by a gerund nounal phrase, I'm used to meeting you everyday.

If a sentence looked like "I sometimes prefer doing nothing to doing something", "doing" is a gerund. If I use the infinitive "to do" form, someone might say "I prefer to do something rather than to do nothing". So, to answer your question, both "doing" and "to do" in this case are verbals, the difference being one is an infinitive and one is a gerund.