When you are about to exchange data with other tools, you should always consider whether it is worth it or not. Compatibility is important but almost all migrations involve the loss of a small percentage of data. Therefore, it is a good idea to compare its advantages to those of productivity, which is best measured in your time and costs. If you gain more on productivity than you lose on compatibility, it is worth migrating. Always plan in the medium run and ask yourself whether you will be more efficient in one year than you are now by migrating to memoQ.
Migration between various editions of memoQ is not questionable as later memoQ versions are fully compatible with previous ones. Migration between memoQ users is similarly straightforward; it is more of a technical issue than a matter of consideration.