I'm one of the former F+ members who is happy enough with FB. The FD people lost some important benefits, but for most of us F+'ers nothing significant changed except we need to fly a bit more for top level elite. But most of us don't have a problem with that.

Some of our folk have reported complimentary upgrades on NW, but I'm not sure about CO. I get comped each year to CO Gold, but I've only flown them once in the last 10 years. Just make sure you have Skyteam Elite Plus to get lounge access everywhere.