I would like to know about the migration tools Tsunami and Metalogix.
I want to compare both of them, can anyone tell me the comparisons?
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Avepoint also has some really good SharePoint migration tools (if you want to do a complete analysis add them to your list). As Cawood said, trials are a good way to go assuming you have environments to support it (remember that most migration tools must be installed on the SharePoint servers; and they may or may not be able to co-exist). Aside from that, there's lots of user testimonials out there and blog posts on migration. Your post was fairly vague so there's nothing that jumps out to me as an article to read.
One thing to mention is what type of content you're migrating and to/from what versions of SharePoint. I'd caution that migration from one vendor may not equal migration from another vendor. They all have strengths and weaknesses, and the licensing is sometimes pretty in-depth. Most that I've seen are licensed by how much you're transferring, not just a license per server, so depending on how much you've got to transfer keep that in mind as you evaluate.
What do you want to migrate? Website, eRooms, Plumtree? Each one has pros and cons depending of the migration source.
We used a lot Metalogix for website migration and works pretty well, but you need knowledge about XPath, and your site needs ID and Class tags to differentiate content areas.