He looks as described in the books -- that is, a lot like Corwin. Powerwise, Merlin seems to go in for a little (or perhaps a lot) of everything: Pattern, Logrus, Shapeshift, Trump, Sorcery,... the list goes on. Plus, he likes to combine powers with computers and, well, perhaps this best describes of Merlin's personality:
"Merlin is the kind of guy who, as a child, decided he wanted to know what it was like inside a running automatic dishwasher, so he tried to open it up while it was turned on. Upon discovering that it had a safety mechanism which shut it off when the door opened, he figured out how to defeat its mechanism so that he could open it while it was running without having it shut off. He then proceeded to do so."
More recently, (right about the time he leapt from about 70th to about 6th in line for the throne of Chaos) he has turned his attention to building better and better defenses for himself. Unfortunately, he did quite have all the bugs out when the two fire angels attacked him. Good thing all his friends were around to save him. Fire angels are nasty though, it took Keverian, Katarina, Martin, Mikele, and Felicia to beat them both. Never fear, our heroes triumphed in the end.
Mikele and Martin's Wedding: As good friend and close relation to both Mikele and Martin, Merlin found himself best man at their wedding (well, weddings, but let's not get picky). Once he overcame the shock of the news, he jumped right into things, throwing both the reception and the bachelor party (livened up by Keverian and Torquil's motorcycle chase of Victoria, but that's another story).