You must be a paid EA shill. Everyone knows the Origin UI is completely ridiculous. It duplicates functionality in Autolog/Battlelog/somethinglog, commonly locks up when you try to use the settings window if something else happens beneath, loves to bombard users with ads at random times rather than just at start up, can crash Battlefield 3 if the overlay is turned on, is capable of forgetting that you own games (the whole resetting entitlements problem), does not allow you to seamlessly join the games of friends or easily get into large group chats or voice sessions, and many more things. To say that Origin's UI is better and less hassle than Steam shows me that you don't have a clue what you're talking about or were born yesterday.
Having Origin mandatory in Mass Effect 3 should be a deal-breaker for everyone. It's not worth the effort considering Mass Effect 3 won't even be all that great. If it were to improve on the original I'd be quiet. It's not designed that way. It's just another watered-down game in a franchise that started strong until EA mucked with it. ME3 is just another Crysis 2 -- a let down compared to the original. I suppose if you're really excited and going to buy it no matter what you should do it and play the multiplayer first before all the cheats come out like they always do for EA games.