The question shoudln't be is it worth getting it, but rather, where can you still find this set?
Several dealers have already sold out on this set and just with luck I was able to snatch up the last copy at another one.
Regarding the guy without helmet, he's one of my most favorite figures. You could use him as Optio, the NCO who usually stood behind the lines, or a whole bunch of them standing together could pray to Mars,Mithras or the Christian God before battle. It is my understanding that people in most countries still take of their hat (or helmet) when in prayer.
Either way, if you don't buy the set soon, you'll probably miss out on it. Good luck finding it on ebay in a few years!