will any of these machines be shipped in time to make an ROI ?
If return on investment is your main motivating factor, then don't mine.
If you want to support Bitcoin and don't need a return in the short term, then, by all means mine with how ever much hash power you can comfortably afford and maintain. Bitcoin depends on mining and if there is no mining then there is no Bitcoin. If all mining is done by a small number of miners with huge hash power then nobody will trust Bitcoin enough to use it.
So the more miners there are, regardless of hash power per miner, the better off we all are.