I did Sparta Prague on FM2013, it was an enjoyable game, and the main reason I did it was because I love Prague I usually go once a year and I have been to a couple of games there.
They do have the best squad in the Czech league (well they did in FM13) They have a good range of players, old and young, but for the league they have a strong team, so if you want a challenge in the context of just winning the league maybe try one of the other Czech teams.
What I tried over the years was to develop young Czech players to make them a stronger footballing nation and to make the teams in the league stronger by loaning out good players to them, thus making the league generally stronger. Over the years I got stronger in Europe and increased the league reputation.