I've never played with an L-dub suppressed, can anyone tell me if it has any quirks or if it suppresses better than a DI gun since it's a piston?

DI guns suppress better as far as being quiet. Piston guns keep the bolt carrier cleaner, but you have to clean the piston. I'm a bigger fan of DI guns personally. But the LWRC guns are very nice.

I have a DI 12.5" and a Adam Arms piston 11.5 both with a Specwar 556K, I can't tell a difference related to having a piston or not.

The Adam Arms has a easy no tool "adjustable" gas block. It only has, off, suppressed, normal. My DI gun has a Micro MOA Govnah. IMO reducing gas for suppressed make more difference than piston or not.

Hundreds of opinions out there.

Really only a difference after hundreds of rounds, the piston will probably be a cleaner system as a whole. Maybe if you're FA and spend ten+ mags or something you'd notice more.

If you plan to shoot suppressed a lot check out the IC enhanced, a little bit more $, but nothing crazy for an adjustable block.

I have a M6A2, in 6.8mm.

Use it with an older generation Surefire 6.8mm suppressor.  No issues, and sounds good to me.  No cycling problems, or signs of over gassing - the SF cans are pretty low backpressure, so they don't need the adjustable gas block I've found.  

The piston system is cleaner than the DI system - to what level of benefit that is - don't know.  If you're not running 100's of rounds out of your AR in a firefight, it doesn't matter.  I bought the LWRC as it was something new to me, and the rifle was set up with all the stuff I'd want to put on it anyway - good stock, sights, grip, handguard.  It's a quality and very accurate rifle, so you won't go wrong buying one.

i've suppressed an L-dub but never noticed any sound difference, you still get ejection port pop and sonic crack.

as for the function, they are fine and seem less sensitive to buffer weight but what i didnt like was how tarnished up the BCG's get. LW uses those plated carriers, nickle boron? and the back pressure gas really made them gross. in fact it seems to lay down a coating of shit that felt gritty and increased friction. i had to scrub the shit out of it with Brasso to get it back to normal.

i went back to DI's uppers for all my suppressed stuff. they get dirty anyway.

I have 14.5 and 10.5 m6a2 uppers that I run suppressed. In my experience, they run much cleaner then the DI guns. I did not have to change or mess around with either upper to run a can on it, never had an issue.

Like others have said, much cleaner, but other than that no real difference.

Personally though, I have an enhanced and spr, and the adjustable block makes a big difference in how much gas you're eating. Although the longer rail on spr makes it a better handling weapon overall, but anyhow.