RIP count to infinity and OSPF

There is split-horizon, poison-reverse, hold-down, triggered update
mechanisms to handle count to infinity problem in RIP.
I am a bit confused about why so many mechanisms are used?when and in
what practical scenarios is each applicable?
Is there a single mechanism which takes care of count to infinity
problem. For example RIP RFC says that triggered updates need to be
used when there are more than 3 gateways in a routing loop. How does
one know in advance which mechanism to use?

Also, I read some documentation which says that OSPF converges quickly
as compared to RIP bcos it is link state based. What exactly does this
mean? How is a OSPF routing update different from RIP update ?


Please clarify.
Thanks