Well on the Molex 0.156 idc connectors I only came across them in old Altec mixers (and in one kit I bought from diypartsstore for the 51x psu, which I "threw out"). The connectors are tough, and well built but I could not use it, so I just put it in a drawer (if you saw my basement you would know that "putting it in a drawer" was my equivalent of throwing it away) and put real crimpable molex connectors on.
Here is a tool from the pinball folks that looks like it is designed for the punchdown molex
http://www.pinballlife.com/index.php?p=product&id=1590 better than the $60 mentioned in the OP but I HAVE NOT USED THIS TOOL (apparently sometimes the wires bend up and don't displace the insulation (that's what I had with a screwdriver) and this tool solves this according to site comment among the pinball crowd.
The main advantage of these is that they allow a "bus", they are inappropriate for PSU connections for so many reasons (hard to use, lower current, IDC questionable contact area, and crimp give great contact area).
Molex has a great document on crimping, a how-to... what happens if you over strip insulation, etc.
I used to tin the wire, crimp the connector, add flux liquid, and heat. I always worried that the heat would change the spring characteristic of the contact, so I was careful but never had trouble. But now, convinced by the crimping "how-to" document, now I just crimp because I am getting better at it, and the document convinces you of the reliability. But the ratchet crimpers are nice (I used to use them on RJ45) because they don't allow you to crush it so much, I think I will get one (more tools!). The key thing is the shape of the anvil and appropriate size. (0.156" vs 0.1") anvil.
Are the ones suggested below good for the 0.156 ot the 0.1" molex crimpable contacts?
Did a search on IDC wire insertion tool (who knew) came up with these that look better too:
http://www.ebay.com/itm/Cable-IDC-Punch-down-Stripper-Insertion-Tool-/290693823247?_trksid=p2054897.l4276
Convenient but looks a bit iffy and specifies 100 wire
http://www.radioshack.com/product/index.jsp?productId=2102881&CAWELAID=120125420000003408&catargetid=120125420000031799&cadevice=c&cagpspn=pla&gclid=CL2tgciW27wCFWvxOgodTzgAGQ&gclsrc=aw.ds
Here is a whole load of them, some have wire de-insertion hooks!
http://www.ebay.com/itm/like/360646664567?lpid=82