OPS should be chosen if you have two major reqts, scalibility and high availibility together.
Replication should not be used if the amount of transaction and number of objects to be replicated is high.Also you should be aware whether current infrastructure cannot support that volume or not.Also Replication may affect application code .

There are certain third vendor good products.Like Shareplex from Quest.
Standby database can also be used as high availability.
Thanks
GP