I really enjoyed aspects of both series. Both are RPGs but with different gameplay mechanics involved. For me I would choose Mario & Luigi just because how fluid the combat system is. It's like turned based with a little bit of semi real time during combat.....kinda. Hard to explain but you all who have played it know what I mean. Paper Mario is closer to traditional RPGs. This is why Mario & Luigi get's my vote because it's extremely unique for a RPG and non traditional which is what I love about it.

Mario & Luigi: 5
Paper Mario: 6

Mario and Luigi. Said so in an article I wrote many years back, for the simple reason that Mario and Luigi is more like what I'd expect from a Mario RPG and not just a generic RPG style series/story with Mario characters inserted in.

http://nintendo3dsdaily.com/nintendoarticles/why-mario-luigi-...

Or to give my reasons more quickly:

1. Mario and Luigi has a similar tone to the Mario series itself. I prefer that comedic tone to the overly 'serious' and 'dark' tone of the later Paper Mario games. Seriously, you could take out the Mario characters and sell the Paper Mario game's storylines as an original novel, and no one would think it was a Mario game plot. Don't like that much.

2. I prefer the graphics style of Mario and Luigi to one in Paper Mario. The characters look more like their normal selves.

3. I prefer the battle system, since it feels like how the combat works in a 2D platformer rather than a generic RPG. And it's much more intuitive to have Mario or Luigi jump over/on an enemy to dodge an attack than to press a button with certain timing like a quick time event.

4. There's less filler in Mario and Luigi, since AlphaDream cut out pointless crap. Paper Mario on the other hand has a lot of sections which seem like they're only included to be 'ironic' or 'make fun of how video games work' and aren't fun in the slightest. Like doing chores or watching a Pianta say he loves his girlfriend fifty times.

I'll cast my vote when it matters the most. To be honest I'm not quite sure which way I'm going to vote yet as I like both a lot.

Mario & Luigi: 6
Paper Mario: 6

I'd say this was an exceptional mashup of series, if I may.
Opinions seem to be split, that's when things get most interesting

Yeah, same here. It looks like a tie so far, though. I'll have my vote in before I go to bed.

Hmm, I'll figure it out...

This is such a tough decision! I'm going to have to think about this for a bit.

I would definitely pick Mario and Luigi over Paper Mario.
however, my favorite Mario RPG was Super Mario RPG.

I've finally decided to go with Paper Mario. The original game on the N64 is just one of those games that I can replay hundreds of times and never get tired of it. I loved Mario & Luigi too, but I've just had more fun memories with Paper Mario

I couldn't choose between them both. They're that good!

...But echoing Kinsale, my fave is SMRPG.

mario and luigi for me. paper mario is great, but i loved the humour in superstar saga for example.

I'm voting for Paper Mario. Both are good series, but Paper Mario games keep me more entertained for longer.

Ugh this ones a tough one!!

I'm going to have to give a slight edge to Mario and luigis. I like the actually gameplay better in that series even though I found partners in time to be a so so game. The other two were excellent though and well thought out. Plus it gave us one of the funniest best enemies we have ever seen. I do love the paper Mario series as well but I like a bit more action both in the field and in battle. Plus what other game has you smash your brother into a surf board and ride the waves!

Agreed. M&L has a slick battle system while the PM battle system feels clunky. The M&L series is also a faster paced game overall.

M&L3 > M&L2 > M&L1 > PMSS > PMTTYD > SPM (Haven't played PM64, will get it soon though)

Paper Mario, Super Paper Mario, and especially PM: TTYD are proof that great writing can transcend gameplay. I like M&L's gameplay more, but they tend to bore me because I don't feel their writing is all that good. And I'm not one to normally put writing over gameplay, either. The Paper Mario games just have better humor, while still making characters I care more about. Honestly, I don't even remember the story in the M&L games, but I vividly remember the Paper Mario games' stories. And yes, I've only played them all through once.

Paper Mario definitely gets my vote.

Mario and Luigi is much better. The controls are pretty tight and interesting and it's more comical and better story-wise.

Mario and Luigi: 11

Paper Mario: 9

Mario and Luigi seems to be winning now.

@CM30, thanks for updating the vote count for me!

I wouldn't even mind if this some how ended in a tie tbh!

Well it doesn't ever end without one winning

However, it could get the honor of having "by 1 vote!" next to the winning title.
Just like Majora's Mask winning over Ocarina of Time...