Join today. This is a really good rewards program for anyone who has to travel on business or travels a lot for whatever reason.
I joined a few years ago when I was travelling in the US and the Marriott group now own Starwood Hotels and the W brand so the choice of accommodation you can gain reward points for and relinquish points for is broad.
I recently had an amazing couple of nights the South of France, Marriott, 4 minutes walk into Monaco with 160,000 points. The room would have usually cost about £400 per night so it was a wonderful reward for using the club.
The app is free to download and very easy to use, you just join; are allocated a membership number then you can start browsing properties by destination and date and then book using your credit card or collected points.
I must saw I have had to change reservations a few times and I have never had a problem rebooking, being charged extra and when I had to cancel a reservation using points they have been returned pretty much immediately.
I once had occasion to email Bonvoy Marriott head office and my issue was dealt with very swiftly so nothing but good things to say about Marriott Bonvoy.
Also when you arrive at the hotel, you get priority check in, extra water and cookies, and sometimes a room upgrade, it has happened.
All in all a great 8 years with Bonvoy Marriott. Highly recommend.