Hm, let's just say if you are willing to fork out real cash (why, oh why anybody would want to do this is beyond me) you'll find they're hit or miss just like the Pistolero said and probably most exerienced players, too. Then I'd go with Teda and look for quality x4/x9 to squeeze the most possible seasons out of him.

No idea about this mobile feature. Will this be introduced for PC play, or are we at a permanent disadvantage playing from our desktops?

However, if you want to play/keep playing for free, there can only be one answer: NEVER spend any tokens on scout players.
- their purchase translates to something like 15-25 tokens for that player per season. With only 35 at your disposal, you'd be able to maintain a squad of less than 3 (!) players.
- from the minute they’re in your squad, they start slowing the team’s average development in comparison with regular decent players
- they don’t perform well enough to justify the cost in both tokens and coins
- they won’t be of any use for more than 2-3 seasons max unless you spend even more

My exerience with scout players has been somewhat patchy, but overall I don't believe they're worth it - far too expensive.