You should get four or five hours out of the SW1000R. And if you don't have the Caltrain switcher, then it has unique features that are interesting. And it also comes with the ex-Metroliner, which is surprisngly quite good fun to use, and makes NEC more attractive to use as a route. But if you have not used NEC before at all, then I suggest doing some of the freight/switching stuff first, with the existing loco, to see if that sort of thing would appeal to you. And you should certainly have a go on the existing NEC freight scenarios ahead of buying OSD (if you haven't bought that already). NB: The NEC route is one of the first made for TSW, and some of the build is bad quality (if you look for it), but generally speaking it is perfectly okay - it is certainly different to everything else, and worth a try.
Oh, yes - I think for £6 for the pair.... you can't go too far wrong. If this is the first time you will run NEC, then it would be really interesting to get your thoughts on how it compares with the most recent route/loco that you have purchased.