I've been using the Snapware Glasslock sets for many years, which I got at Costco. I prefer to microwave in glass - no stains or bubbling like plastic. I believe you can get a plastic version of the Snapware, too.

As noted, the Glasslock lids are not totally liquid-tight, so I just don't use them for anything liquid. Thus, I don't have a big problem getting to work with them sideways in the pannier, in a thermo bag, except the food falls to one side. If I had soup, I think I'd use a purpose-made Thermos-type thing, maybe keeping a glass bowl or huge coffee mug at work you can wash for reheating.

Finally, the gaskets in Glasslocks have to be removed periodically for cleaning. The silicone rings sit in a channel, and will gather food and liquids in the channel, and lots of gross black stuff will grow underneath. I use a dull blade like a butter knife to pry the seal out. I don't think the lids are dishwasher safe, but I haven't had a problem on the top shelf if I set it to Cool Dry.