If you want an oasis to escape from, both FS and MO are your best bet. Make sure to book a strip-view suite to get a sense of place. Avoid entry-level rooms or suites at MO, as they are on lower floors and have awful views. FS in Vegas is particularly accommodating in terms of upgrading (and upselling), so if you want to keep an eye out for specialty suites, this is the place. Both hotels are not your typical Vegas hotels, so if you want that - a Tower Suite at the Wynn is excellent. The Tony Chi designed Skylofts sit on top of MGM and had some better reviews back in the day - I honestly don't know what it is like these days. I would be careful. So, from your comment I assume you might be happy at the Wynn. It's a fun hotel, if you take it for what it is. But you will have to book a higher category to get a comparable experience to MO for example. If you book a standard room at the Wynn - you will invariably end up waiting 30 min+ for check-in.