MORT is a fun introduction to the Big D, and an entertaining tale to boot, featuring derring do, daring dudes, and a couple of lovely satirizations of tropes, as is Pterry's wont. If you enjoy the Discworld stuff and somehow haven't read it, you will like it.
As the lattermost (maybe, I think?) of the Moist von Lipwig tales, MAKING MONEY drops the reader into a later-days version of Ankh-Morpork, where many of the machinations have already been machined, so it was a lot of adjustment for me, since I have only read a scant handful of the series thus far, and hadn't met any of the principals previously, but knew who they were by reputation and fandom exposure. It's kind of like a cheerfully Saturday-morning-cartoon version of Steven Brust's "Taltos" novels, with the rapscallion going straight, mostly.