Hi Vegeta, seems we have a lot of TV characters recently on the forum .
Yeah, Just as I mentioned in a post I just replied to, have a LP guide is not always that useful and especially with Myanmar, the current one is out of date, but for the historical and cultural explanations are of course still correct.
I can't tell you that hiring a guide is a must, you can also enjoy the beauties of Bagan without anyone and just reading a bit through your book. But I think if you want to understand everything that the site has to offer and discover places or art work that you would not see if not shown by an experienced person, it is for sure better to hire a guide.
Going to Bagan, Angkor Wat or sites like Borobudur is not like going to the beach, where you can just enjoy the nice landscape and take a bath, if you want to get it all and take advantage of your maybe once in a lifetime trip to Myanmar, you better hire a guide.
As another member mentioned about doing the sunset or sunrise in a hot air balloon in Bagan, you may have one opportunity to do it, so even if it cost a bit more, I think you should do it.
This is only my opinion and advice, after you shall do whatever pleases you. For my personal experience, I took a guide the first time I went there and of course I don't remember everything that was said, but I definitely don't regret taking one.
Enjoy the 2000 pagoda's