Hyatt Osaka is certainly more convenient than Kyoto for going to the places you mention, especially Universal Studios, for which, I believe, there is a shuttle you can pay for. Also, you can take the free shuttle to Umeda (Osaka station) to visit Yodobashi Camera, (superior to den den town, in my opinion). Alternatively walk about 4 minutes to the nearest subway station (nice wooded walk, bridge over the road). For Osaka Castle, you'd take the subway to Osaka Business Park. Yes, the Osaka Hyatt is physically a little rough around the edges - it's showing its 20 years - but the staff is great, and it's much cheaper than Kyoto.