Never heard of them for fsx. Quick google just showed an fs2004 add-on.
Looks good for fs2004, but not sure of their compatibility with fsx. You do seem to get a good selection of aircraft in the package though.
I have the pmdg 747 and captain sim 757, but I don't tend to fly airliners that often. The pmdg 747 is expensive, but is probably the most comprehensive version of that aircraft you'll find and it can be flown without spending an hour setting the fmc, but you'll get the most out of it if you use all the systems.
As tubliners are about systems management for me, so I like the systems to work.