So here's some constructive feedback after I investigated what's in the pack and used/tried all of the extras either on my phone or PC:
Ringtones & Message Sounds
Disappointing. Most of them are bland and not very distinctive/unique. They sound as if my phone speaker broke and distorted the sound. IMHO they should be more unique, more melodic rather than buzzing FX sounds. For ringtones it could be parts of the actual in game music, 10-15 seconds cutouts. The message sounds are not too bad, but could also use improvement and better selection of tones.
Windows Sounds Theme
That's actually quite good, I like it. Not much to comment on - well done on this one!
Wallpapers
This is just selection of screenshots. I must say that the choice isn't too good, I've seen hundreds of much much better ones posted by community members. They are plain, have no logo, no game name on them, just plain screenshots from the game. It almost looks like they were prepared in a hurry and not much care was taken to select some really good looking, well framed shots.
Screensavers
They are the best item from the whole pack. Especially Space and Hyperspace ones. I like those, but one has to wonder - who actually uses screensavers nowadays...?
Digital Artbook
Not included. Was DA part of Mercenary Pack at all? I know it was part of something I purchased, but I cannot remember what... Premium Beta pack or Mercenary Edition (which was part of PB pack if I'm not mistaken). It's all a little confusing.
I must honestly say that I am somewhat disappointed with the extras. I have never complained about Frontier actions and I was always trying to be understanding and supportive about their decisions, so this is the first time I feel let down a little. This extras pack just makes an impression of being prepared in a hurry and not thought out in great deal.