First of all, welcome...you've found the right place to start your research!

Second, there is no one answer for everyone - those two programs are probably the biggest two hotel programs in the world. Or, at least the most popular among folks who stay across a wide selection of hotel types from roadside motels to 4- and 5-star hotels.

It's like saying which is better: UA or AA. Those two are very similar in their primary mechanics, and that's no coincidence. Everybody has an opinion, but it really comes down to which one works better for you.

Answering Goldarm's questions is a good start: first and foremost, where will you be doing most of your paid stays, will they be business or leisure, and at roughly what type of hotel within the chains will you be staying? (e.g., Full service, extended stay, midscale, etc.)