Biggest drawback is that none of the commercial clients will implement support for it, that's what killed it for me (SecureCRT developer VanDyk told my company NOPE!) due to license issues :(
Yeah, what's the point of creating a great, mobile focused alternative (or enhancement, however you'd like to describe it) to SSH if no one will implement it on iOS because it's GPLv3?
If a company want to create a proprietary client, they can always do that. They simply has to pay programmers to do the work, rather then freeload on the work of a research university.
Alternative they could collaborate with the research community, adding to the common knowledge in computer science and security on a deal where everyone share in access. For security and encryption software, I find this deal to be quite necessary for everyone involved and are thus glad with projects license choice.
