I think Beast Master remains disappointing, but you CAN make it work if you think of it as either being able to be in two places at once (but still with only one set of actions), or if you're going for a flying mount. It's conceivably possible to get a flying mount at level one, but it's hard to do. You can guarantee one if you're a Ranger by level 3: a giant owl is CR 1/4 and thus a valid pet. It's even Large, so you could ride it as a Medium creature. If you're a Small Ranger, a pteranodon (a recent "D&D: Ranger Edition" pointed it out to me) is Medium and can fly. This has advantages for actual dungeon delving, because you could ride your Medium flying mount into dungeons that are built to accommodate Medium creatures.