I use 1Password on my iPhone & iPad only. The Cloud Sync works perfectly across these devices. Have not tested it on a PC.
No need for me to purchases the $9.99 addon or any other addon. The standard App suits all my needs perfectly & then some.
For iPhone the 3D Touch implementation is spot on.
For iPad the multitasking (Slide Over & Split View) is handy as well.
Great App period.
What do you do when you want to login to a website or app on a PC?
I use LastPass, and all my passwords are unique 15-25 digit mumbo jumbo. I'm sure 1Password can sync to desktop just fine if you pay $50, but $12 a year for access on all platforms with LastPass seems easier to me.