Well, lets see?
First I was having issues with Hermes 223 v3 but after I used DOP-IOS to update (and trucha patch) the few out of date IOS's on my Wii - 36 merged with 37 was good (I'm now on v4 - 38 merged with 37).
Then I read that if IOS60 was trucha patched the system menu on 4.1E should be able to run unsigned code from the SD.
SignCheck said I was already patched and upto date but I couldn't copy or run wad's installed by wad manager off the SD.
I used DOP-IOS to re-install (and trucha patch) IOS60 (after using bootmii to take a backup) and now all is good.
That's 2 problems in as many weeks DOP-IOS has fixed for me, so I now consider it an essential tool. However it's a powerfull tool that could brick a Wii if used carlessly so it's guidence notes are a essential read as well.