Only been there once but it was awesome! Stayed at the Hard Rock Hotel, theres all kinds of music memorabilia all around and they play awesome music in the elevators so we were always dancing!!! So much fun!
I went with my family last summer. We agreed within an hour of being there that we would never stay at a Universal Resort again. We stayed at their Cabana Bay budget resort, so not the highest quality resort. But the service was terrible and we were nickeled and dimed everywhere we turned. Never again would I stay at Universal. I love the parks and will always visit the parks if I'm in that area, but I would choose Disney always over Universal for service alone.
Loved the Hard Rock! Loews Resort was very nice as well, they had a very tropical vibe which I loved. Your room key also doubles as a FREE fast pass for both hotels and there's free transportation via shuttle or ferry to the parks. The prices are a bit hefty though but the fast passes are definitely worth it.
I stayed at Cabana Bay. It was affordable. The resort itself was "meh" but I am a HUGE Harry Potter fan so none of that mattered to me. I just loved that the resort got me into the park early and was convenient...giving me the most possible time at Hogwarts.
I have stayed at the Loews Portofino Bay Hotel and the Hard Rock Hotel. I loved the Hard Rock so much better it had a younger vibe to it. I also love the fact of staying at a universal hotel you get early park admission for Harry Potter World and Universal Express Unlimited to skip majority of lines in the park.
I live in Florida not too far from Universal so we have season passes. We have always stayed at the Portofino resort and have loved it! We usually stay for a few days and get a pool cabana one of the days and just lounge around. The new resort Royal Pacific is supposed to be really nice as well. With the Royal Pacific, Portofino and Hard Rock you get the early admission and the express passes.