There are a lot of variables -- including what time of year you are going, do you have
AAA so you can get another discount, etc.
For our family of 3, it is absolutely worth it. We love to bypass the long lines as many times as we want for each ride, we love the convenience and ease of going back to our hotel whenever we want to, we enjoy the onsite hotels and their amenities, and find it to be well worth our $. That said, we generally have a room charge of $150-$175 per night, with either AAA or Annual Pass rate.
SOG is also actually a special situation, most families cannot stay there, so I'm not sure how comparable it is to other facilities, and I believe your rate is based on rank, so whether it is a price you can expect elsewhere, I don't know...It seems inline with the values at WDW and other area hotels. If you want to compare the Universal hotels, they are comparable with a WDW Deluxe (actually, I would say they are superior).
You can probably structure your day (be there before opening, have a clear ride plan), so that express pass is not essential. People do it all the time, with great success. I imagine the opening of Harry Potter will have an effect, but it might make the other lines shorter.
All I can say is, having stayed onsite, I don't think I'd be happy off property. Since you haven't stayed onsite and aren't concerned about the hotel, I'm sure you can do it, but I advise you to have a plan to make sure you are able to do everything that is most important to your family.
Have a wonderful time at Universal!
Maria
