Hey Chaddy
For a minute I thought you wanted to compare the 3050 and the 3075, anyway!...
Well firstly the 3075, the continuity and insulation resistance tester, good all round meter's in the 3000 series, the 3075 being a jazzed up version of the 3050, also a good meter, the 3075 has backlit added to it along with extended battery life, I'd imagine it is just as good as the 3050, if not better for it's addition's..
the 5404 ELCB tester, another good tester, can highly recommend, it's now the older one in the series, there is now the 5406 which will also test DC sensing RCD's, useful I'm sure, but not found it really necessary myself
Hope this helps