Ultimately you have to play to your teams abilities and the conditions. If your pitch is a batting paradise then batting first, getting a total and using scoreboard pressure is the way to go. If you have a deck that nibbles around maybe a bit damp to start with and you have a decent bowling line up then it's a bowl first job.
I remember winning a 2nd XI league with a weak bowling line up and a strong batting line up. Our pitch was a road but the ball swung around early on. We simply had a line up of swing bowlers who could take wickets first up. We weren't quick enough to stop runs when it didn't swing but we hoped to do enough damage before the oppo got on top and restrict the score. Then once we had a below par target we'd leave it to the batsman to chase down. Plan worked very well for a number of years. I remember doing something similar a few years later with a stronger bowling unit, essentially heap loads of pressure on them first up and hope they crumble. In that instance we had a deck that moved around a bit and generally got better as the game went on. We were just as good setting targets and really you want to be flexible in your game plans according to conditions.