which rotary cutter and mat to buy and/or to invest?

random-charm - I totally abuse my big Fiskars mat.  I don't always store it flat, I use it on the carpet, I walk on it... right now my trash bin is sitting on top of it... and it's been fine.  I've even stacked bins of fabric on top of it and then slid it under the bed.  I've had it for over a year and it's always out since it's so huge I don't have a good place to keep it so it just stays out.  The dogs even walk across it.  I once used it to cut like 400 strips of fleece.  I would recommend the big Fiskars one to anyone who has a table large enough to put it on.  I just like the Gingher mat better because it's twice as thick so I don't have to always have a "proper" cutting surface and it works as well on the carpeted floor as on a table, which I think is worth the extra $

I originally bought one of the folding Fiskars mat and it STUNK up my house so bad my husband made me take it out to the garage.  It was so gross.  I called Fiskars and they said sometimes that happens if they don't bond right? So they sent me this one (same size, but not folding, it's yellow on one side and green on the other) and it doesn't smell at all.  Fiskars is definitely a good company IMO

FYI on warping Olfa mats. If it happens, lay it on a hard floor in the sun. Works every time.

Thanks yorkiemischief - That's good to know. I only have hard floors so it really doesn't matter where I use it. I've actually got mine on a large frame on top of a 36" high shelving unit which is working great, so now I will go about building something more sturdy.

betsyb2 - I've tried that . . . maybe the sun is hotter where you live? I may just be too far north for that trick to work. One of the corners has also cracked off on mine, how weird is that??

clothedinpurple - if you are having trouble with a thread or two not cutting IME it's more likely a knick in your blade rather than the mat. Try changing the blade and see if you still have the problem.

I had the same thing with mine...I should have thought to call the company.  It did eventually go away though.

I've tried that but the only time it leaves a thread is over the crack in the middle so I'm sure it's the mat.  Thanks though