If I would know anyone to say one method is trash or the other, it's you.
But also, you're not explaining why it can cause bricks. Genuinely interested other than, "ModMii is a PC based app that uses external tools"
I don't know exactly why it causes it bricks, there could be many reasons. It's not my tool and I don't recommend it so I have no reason to investigate causes.
I can speculate though; it could be installing a stock IOS80 on 4.3 Wii's that were originally Korean and poorly region changed; this would cause 003 brick (and in fact official updates could cause this kind of brick too, and RC24 patcher as well; I have talked to the RC24 team about making some changes to handle IOS80 the way modmii does to control for this risk, it's on their to do list). It could be doing what Waninkoko's old 4.1 or 4.2 updater apps did in the past, and retrieve the latest IOS60 or 70 when updating (instead of retrieving hardcoded unstubbed version numbers), but later those IOSs were updated to be stubs so would cause brick if still running 4.1 or 4.2. Another potential reason could be the old ahbprot network init bug, this was an issue when apps launched via an older HBC with ahbprot arg's would sometimes freeze if the Wii didn't have WiFi enabled. If running a tool like IOS236 installer and it failed it wasn't an issue; however if the wii froze in the middle of say a priiloader installation that would have led to a semi-brick. Or if a freeze is experienced in the middle of anything crucial.
Take it all with a grain of salt, as I said this is speculation and I am NOT a pimp my wii expert (I would argue such a thing doesn't exist, it's not like it's open source even though it should be as it is almost certainly using GPL code). I have just seen enough brick reports over the years to know not to recommend it. I wasn't the one to give it it's infamous nickname "brick my wii", that was earned all by itself (I almost wish I could take credit). In fact I generally try to avoid using that nickname these days as too many people have implied I'm just jealous, lol. Anyone who knows me knowz that I don't care about that, if that were true I wouldn't recommend wii.guide as often as a do as a very good ModMii alternative (albeit without as many bells and whistles).
In any case, I have wasted far too much time already discussing PMW. If anyone still wants to use it by all means go ahead.
People just want an all-in-one solution that runs ON THE WII ITSELF, without the need for a PC. That's where PimpMyWii shines. That's my point in all of this.
RUNS. ON. THE. WII.
okay, so how does PMW help u format your sd card, set up and launch an exploit and make a nand backup? What good is a tool that "runs on the wii" but doesn't help you run it in the first place or skips important steps? An all-in-one tool that runs solely on the wii will NEVER be able to do those prerequisite steps. In theory if pimp my wii were perfect, which it isn't (remember those brick reports you conveniently ignored?), users would still need help getting to the point of launching pimp my wii.
In any case, until I see a syscheck of a wii that had pimp my wii run on it there's no point debating. I highly doubt the end-result is optimal. I just tried finding the latest version of pimp my wii, and the best I could find was something 8 years old, and that was after avoiding a bunch of shady links.
Unless someone actually shares some NEW information like the requested syscheck from a Wii that has used PMW I do not plan on continuing this conversation any further.