I haven't yet completely watched Martin's talk on CRDTs, so I might come back and stand corrected. For now these are some well known trade-offs
A central server: Most OT algorithms depend on a central system for intention preservation. CRDTs are truly distributed and need no central server at all.
Memory: Traditionally CRDTs consume more memory because deletions are preserved. OT lets you garbage collect some operations since a central system is already recording those ops and sequencing them as well.
Analysing and cancelling ops: OT lets you easily analyse incoming ops and modify/dummy-ify/cancel them without breaking the consistency. This convenience is not necessary for most cases, but really important for rich-text editing. For example when someone merges a couple of table cells when another user is deleting a column, we need to analyze these operations and modify them so as not to end-up with an invalid table structure.
A central server: Most OT algorithms depend on a central system for intention preservation. CRDTs are truly distributed and need no central server at all.
Memory: Traditionally CRDTs consume more memory because deletions are preserved. OT lets you garbage collect some operations since a central system is already recording those ops and sequencing them as well.
Analysing and cancelling ops: OT lets you easily analyse incoming ops and modify/dummy-ify/cancel them without breaking the consistency. This convenience is not necessary for most cases, but really important for rich-text editing. For example when someone merges a couple of table cells when another user is deleting a column, we need to analyze these operations and modify them so as not to end-up with an invalid table structure.