Okay, first off, I spent over thirty computer-hours personally, plus had no less than twelve other individuals logging hours of time trying to get these mods to work together, so I'm a bit offended by a) your statement about 'lies' and b) that you honestly believe that I did no testing on this bug issues.
Second off, I've asked a couple of times which versions of both mods you are using. Just saying 'the latest version' is insufficient data. Part of conducting an experiment includes releasing all data for peer review.
You aren't the only one with a mod pack. Mine's been up on the FTB Launcher since May. None of my users, or myself, was able to ever get this to work. Furthermore, King Lemming mentioned that the problem was because of how Microblocks and Liquiducts/Conduits function, and that there really wasn't anything he could do about it. So I'm really interested in how you managed to pull this off. Details would be nice.
Umm... I sort of agree that Immiblis microblocks is/was kinda unstable but you can make them work. Also sure KL says it can't be done but the problem does not lie with KL now does it. We are talking about Immiblis Microblocks here. Maybe Immiblis found a work around (probably a hacky one) that happened to work but not compromise the function of them.
Now why you are getting players crashing, I think I know what's up there.
One of the versions of Imb's micro blocks (not sure which) for some reason had Microblock interaction and exrtra cuttable block types disabled in the config. If the server side was to activate one or both and someone placed a cover using the new blocks or covering a conduit. Those who do not have it activated client side would crash whenever they got in to render distance of the microblocks that or they just wouldn't render.
That was a problem the server I usually play on had. The server owner decided to activate the additional mod textures and decided to decorate spawn with a few of them, this in turn caused everyone to crash when they /spawned. Luckily my server uses it's own mod pack so changing and exporting the block config to the players clients was easy... well easier then if we used a standard pack becasue the pack maintainer is in control of updates.
If you did ship the exact config out to players well I have no other ideas to what the problem could be.
P.s I don't think you are "saying lies" you seem to genuinely have had problems with the mod and they are/where actually real problems.
Forge multipart while it seems like there are less features it's not just a micro block mod it's much much more. The sheer fact that you can have certain entities share a space (e.g torches) and still be functional, opens up a load of possibilities that also aren't just aesthetic.
Hopefully modders get right on to utilizing them to the full extent needed. While ATM Imb's Microblocks is superior, Forge Multiparts has WAAY more potential, of course if modders intend on utilizing it.