1. The IET Code of Practice (Edition 4) outlines a Soft and Hard test for Earth Continuity on Page 92. It does NOT say that one is better than the other.
2. The COP also says in para 4 of page 92: "It is very important that these non-safety earthed metal parts are not subjected to the "hard" test, otherwise damage may result". Now, even the most competent PAT testing professional cannot be expected to know which of the metal parts on an appliance is a safety earth and which one is a functional earth.
By the time a tester finds out that he has inadvertently connected to a functional earth, it is too late as the equipment might already be damaged.
3. More than 90% of problems with appliances can be picked up by a Formal Visual Inspection (FVI). The testing is important, but arguments about which PAT tester is better for the job is quite counter productive and moves the discussion away form what is really important - a good understanding of how to carry out FVI properly.
On many occasions, I have seen PAT Testing carried out with testers that cost more than £1000 where the plug was not opened up and the fuse checked.
4. With modern equipment, the definition of "IT equipment" is a bit vague. In our experience, a "hard test" for Earth Continuity carried out on PDQ machines, toasters and Hi-Fi equipment has resulted in permanent damage. (The toaster was an intelligent one with micro-controller built in).
For all the above reasons, I recommend the use of the 200 mA soft test for all Earth Continuity tests.