While it is always good to have alternatives, focusing on one chain accrues long-term benefits. Hyatt is generally considered the best, most rewarding program, but has higher costs and a limited footprint.

Living in the U.S., if you get one personal credit card (including the no-annual-fee Chase Marriott Bold) and one business credit card (the business Marriott AmEx is $125 per year) (includes notional businesses), that gives you 15 Elite Qualifying Nights (EQN) annually each, a big headstart toward Platinum Elite, which requires 50 EQN per year. Ten years & 600 EQN, and you are a lifetime Platinum.

But don't abandon your backup chain(s).