For one, it's more likely that you'll get type ins and the like from a .com as it's more popular, other than that, I think it's just a standard in domains. I'm not a big fan of country TLDs myself.
Also, ive considered getting a .info domain, as well its an informative site! Are there an restrictions what you can use this extensive for? And is it really...that bad?
I think you should try and get a .com because if you have .co.uk, and the .com is taken, people might think that it's an "imposter" (not really but yeah) and I think .com's are more professional, and maybe so are .net's but I wouldn't go with .co.uk, unless it's a UK company for UK residents.