I really like the California Faucets thermostatic valve i used recently - well built, separate controls for two outlets, both with higher than typical flow rate, and a large central temperature control lever or knob surrounded by embossed numbers for ðF styled as if it were a fine watch. They also have a huge selection of styles, finishes, and either round or rectangular bezels.

I've also used one of the Hansgrohe thermostatic valves that used their universal box - also quite nice, though I think a chrome-plated plastic bezel is a bit cheap for something priced as an upscale item, and I'd like temperature markings (isn't that part of the point of having a thermostatic valve, knowing what temperture the water will be?) This one uses a single lever to control 2 outlets, but it still works well and incorporates water volume and a diverter into the same control, and yes it can send water to both outlets at the same time at any proportion. It's designed so the innards of the valve are all accessible from the front, and can easily be serviced or replaced without ripping out tiles or the back of the wall.

The Kohler and Grohe thermo valves I used a few years back have both been discontinued, so not much point discussing them here (there were both good).