More like the first examples I thought of. There are tools that are best in class and capabilities not usually found in other mods (mek isn't common in packs I've seen). But it doesn't have the level of content of something like… heck, forestry. Think more like Extra Utilities, not Thaumcraft. It gets its power from giving you a good toolbox and letting you at your own problems (like redpower); sure it's suffered from the option-narrowing nerfs, but it's still a good general purpose/utility/automation mod for filling in gaps in capability or providing alternative solutions. And if the nerfs are a problem? New Dawn
Mekanism is pretty common in non-FTB packs. I think its unfair comparing Forestry to any tech mod really, as Forestry gains almost all of its features from worldgen. I'm sure you will struggle to find any tech mod that comes close to it in terms of how much content it has. If you were to compare Mekanism to EnderIO, Buildcraft, IC2 and the TE suite, then you'd find that its not that far away really.
And I definitely agree with Botania not being the easiest of mods to deal with if you have aesthetic building in mind. Most of the automated builds I've used result in a horrible mess of redstone, chests and sparks.