Gears 1-3, the single-player gameplay didn't change very much at all, aside from refinements in slightly different weapons, etc.
Mass Effect was a RPG, but with third-person elements. Mass Effect 2 & 3 went further into shooter/action from RPG(in terms of playstyle, though there's still plenty of RPG-style things); the biggest difference you'd notice in the RPG elements from 1 to 2&3 is that 2 did away with a lot of the skills that you could enhance, and 3 did away with even more.
Really? Mass Effect 3 ADDED more enhancements to skills. Mass Effect 2 streamlined everything so you didn't have to choose between a 2% increase in health regeneration or an additional 2% cooldown on your biotic abilities.
http://www.youtube.com/watch?v=pMKUUUvjjzo Fan of: Steelers(6-time Champions), Red Wings(11-time Champions)
I rarely get bored playing games, but Gears Of Wars was one of the games I just couldn't get into, & got bored very quickly. People love Gears though, so as Sun said.. It's what type of game you're after.
'I wrestled with an alligator,I tussled with a whale,only last week I murdered a rock, injured a stone, hospitalized a brick. I'm so mean I make medicine sick.'