Perche

I agree with you that because of the overwhelming number of tourists, October is better than September, pretty much anywhere in Italy, except if going to the south for the beach, or to the north as in Torino, where there are few tourists.

I said the Westin Rome is in a reasonable location, but not the best. It's certainly close to the Borghese Gallery Park. I think in general, people would consider Piazza Navona, the Pantheon, Campo di Fiore, the Coliseum, and the Forum to be the center of historic Rome. You can sort of draw a circle that would include all the main places, including Piazza del Popolo and the Spanish Steps. The Westin would be outside the circle. You can get to the border of this imaginary circle at the Spanish Steps by walking just about ten minutes, so it's not bad.

But since at ten minutes you'd just arrive at the border of this circle, you'd have to walk a 35-40 minutes to get to the Forum or Coliseum. It's a little over a mile to walk to Piazza Navona, which is sort of dead center of the historic area. It's one and a half miles to Campo di Fiori, or to the Tiber River at Castel Sant'Angelo, and about an hour walk to Trastevere.

You're not really amidst the typical major sites that people generally want to see. Instead, of the Spanish Steps, you more or less half to walk a half hour to get to the places most people would want to visit. It is certainly fine for someone who doesn't mind an hour walk back and forth to eat near the main sites, or someone who doesn't mind taxis (although makes you miss the neighborhood). That's why I think it's a reasonable location, but not ideal. It's not like staying in Testaccio.

About a 20 minute walk from the Westin gets you to the Pantheon. The Pantheon and Piazza Navona sit as much at the dead center of the loop as can be. It' not a long walk to anywhere, with the exception of the Vatican, which is over 45 minutes on foot from the Westin, over two miles still doable, but not as doable as from Piazza Navona, where it is just under a mile.

There are some great hotels near the Pantheon. They will generally cost much less than the Westin, and when you you step out you are immersed. No need to walk 20 minutes, take a cab, train, or bus because you'd already be in the center of it all. The Westin just adds 15-20 minutes to walk to most places. It's not in the ideal location in my opinion, but close enough. I'd walk back to the Pantheon from the Vatican or after eating in Trastever at night, buy if I was staying out there at the Westin I would have to take a cab.

So, no knocks against the Westin Roma, it is not in the best location to stroll outside and find a great coffee shop for breakfast, but it's in a reasonable place to sample Rome with some effort. Close enough that I wouldn't hesitate to stay there on points, and I'd be very happy. I just wouldn't stay there if I had to pay cash out of pocket.