I've used both, and prefer the Spectralock, hands down. First off, with the Quartzlock, if you're not careful, you're going to have dried grout on the face of the tile. First time I used it, I almost got caught, and that was only after grouting about half a tub deck ans splash. I had to really scrub to get it off the tile. Secondly, Quartzlock has had issues with wet areas, where if too much water was used in the cleaning, or if a bathroom was used too soon after grouting (they demand a week to 10 days to dry), the grout became soft and wouldn't harden up again. Another thing I don't like about the Quartzlock is that you can only use a little bit at a time. It tends to dry out and roll up as you try and grout, rather than spread, the way it should. Additionally, as expensive as the Spectralock is, the Quartzlock is about twice the price. About the only thing the urethane grouts have going for them is they're a one part premixed open the pail and go, whereas the Spectralock has to be mixed.

Get the Spectralock.

One last thing-- If you can, instead of the Pro, look into the newest generation Spectralock-- the 2000IG. It just came out on the market a month or two ago, and is actually being shown to the public starting next week at the industry's convention in Orlando called Coverings. I know a couple of people who've used it, and I'm told it's extremely easy to work with. Even moreso than the Pro.

Bill:

First, thanks for your advice and recommendation. Your and Mongo's posts are invaluable to DIYers like me.

Regarding SpectraLock 2000IG:
Laticrete's website indicates this is for industrial applications where chemical resistance is needed.

My email correspondence with Laticrete technical desk provided no guidance on the most appropriate grout for a tub/shower alcove. I know Laticrete PermaColor has been talked about positively, but it is cementious and I was thinking an epoxy would be better in terms maintenance and color fastness. This is a Kerdi install with Crossville rectified porcelain tile.

TIA

ntruro-- Two things. First off, it's called an industrial epoxy because it now meets AND exeeds all specs for 100% solids epoxy, and industrial (and commercial) use is where the big money market is. It can still be used for residential use. Not sure if they have the smaller units out yet, but if they don't yet, they will soon.

Now, that all said, my own personal feeling (and this IS personal-- not professional) is that with three general exceptions, epoxy is a hugely expensive overkill for residential use. Those exceptions are for tiling countertops, if you have pets that are prone to "accidents", and third, for a shower where you have problems with minerals in the water. Other than those three situations, cement based grout is plenty good enough, and the PermaColor goes a long way past alot of the other cement based grouts toward stopping the more common problems, like mold and mildew, as well as colorfastness.

We had sand grout in a bathroom and I'd never do it again. We put epoxy (SpectraLock Pro) in the kitchen and loved it. Never had a problem with staining or looking dirty.