I use both a Megamat and a Mondomat (4.5'x9') at my game table -- as well as a projector on a White 1" square Easel Pad of grid paper.
For most people the Mondomat is ultra overkill. It probably is for us too - but it fit my table nicely so I grabbed it.
From time to time the Megamat is not as large as I would like - but for most purposes - it's the "right" size.
The smallest vinyl mat, the Battlemat, is too small in my opinion. Other groups may have a different opinion.
I bought a Flip Mat at Gencon as part of Steel Sqwire's complete binder kit several years ago. We have used it when we move our game outside during the summer on the patio. It's a little small for general purposes, but for use for a single interior encounter or a small scale exterior encounter, it will serve.
Quality wise, the Flip Mat is nice but the creases can interfere. It folds up extremely well for transportation in a binder, which is perhaps its greatest strength.
It accomodates both wet and dry erase.
Overall, I like the product for some uses. If my game hosting moved around a lot, it would certainly be more convenient (except my game doesn't move. We play in a gaming room reserved for that purpose here). I might use it in the car for some backseat DMing on the way to GenCon (in fact - this August is probably the next time I will actually use my Flipmat for that exact purpose)
But for everyday use during a session? No. It's still too small for that purpose and a Megamat would serve you
much better in the long run. I have had mine for...14 years? Something like that. The previous one I had, I destroyed trying to clean it with nail polish remover. (Hint: Don't do something stupid like that. Ever!)
If you wanted to try something else fairly cheaply, I could also recommend Gaming Paper. You can see the product with videos at
Gaming Paper
For some purposes, gamgingpaper would serve well. I still think a Megamat or a Mondomat are FAR better products at a better overall value over the life of the prodcut - plus they cushion die rolls nicely so you aren't chasing dice across the floor.
That said, some people just don't have the $100 to drop on a Mondomat or the $30 to drop on a Megamat - but they do have $4 for gaming paper.
Verdict: Get a Chessex Megamat. If you take reasonable care of it - you'll still be using it 15 years from now.