TS:JC is a fine game, so long as you aren't expecing more than an electronic version of a miniatures wargame.
The graphics aren't spectacular, but I generally don't disqualify games based on that. Some of the best strategy games I've played int he last 5 years had graphics that weren't anything special, throwback sprite driven interfaces on top of highly complex, enjoyable re-playable games such as Europa Universalis II.
Unfortunately the gameplay isn't all that spectacular either. The campaign mode lets you save your troops from one mission to the next, in theory gaining experience, but in reality your troops will very rarely gain in experience from where they start at the beginning of the campaign. The general equality and game balance of the missions, while good for that battle, will prevent your units from gaining very much experience. You can either use experienced understrength units or replace losses and go into the next fight with green troops. All in all disappointing.
The individual battles are fun enough to play. I got a good 20 to 30 hours of enjoyment out of these which is all you can really hope for from most games today I suppose. Perhaps I'm being a bit harsh on TS:JC, because I was quite disappointed with Civ 4 too. It really depends a lot on what you're looking for. If you want a sim of a tabletop miniature game, this might be right up your alley.