I think where you are missing the usefulness in factorization is not in it's end-game, it's in the early to mid-game. Few other mods can you setup an ore-increasing systems in the same amount of time. The slag furnace is a very, very under-valued piece of the mod for that reason. It's ~1.3(ish)x output, but you can use it right from the start, as well as leaving behind smooth stone for building. Why it's not the third or fourth block made is always beyond me. For the mid-game process, you don't have to use the crystalizer, it's more of a 'If you really, really want the best output...'. This is typically where I drop my gold, since I don't often need it which gives it time to get the 3x-5x amount. For most other ores, I simply let it finish at the reduced chunks process. A common mistake with the crystalizer, however, is not using all 5 non-sulfur slots. You can fill 5 slots in the outer ring with the same ore and they will all pulse at the same time. It's nice when you turn 5 chunks into 10 gold, that came from 2 gold ore.
Also, one of the other blocks that is very, very unique and useful is the Heating block. You can put multiple next to the same block to make it faster. A 4-heater furnace can give the TE furnace a run for it's money.
Two of the functions of the pocket crafting table are also often overlooked. With a single button, it will try to arrange all the blocks in the grid in a circle. It's nice being able to drop in 8 refined iron, hit a button, and pull out a machine block. Have 64 refined iron but don't feel like doing the split/split/split, or worse, right clicking 8 times each spot? Just drop a single one in each of the needed slot, drop the rest in any of the spaces and hit the balance button. Voila, 8 in each spot. For blocks of metal, I find this method very fast.
As for the barrels, I find them very useful for items that don't really fit in a chest, like putting two barrels with rails and ties next to my rolling machine, or three barrels with tank parts (walls, levers, glass) in the starting area of where I'm building a room. Again, sometimes the usefulness is better early game, as I usually start off with a barrel and drop in stone bricks, starting my actual major building when I finally notice I've got a good amount. However, if you are not a visual person, I can see this being more of a turn-off.
When it comes to the router, I feel like it's like turtles. Yes, you can create an amazingly efficient sorting system, however with the time spent you could have already setup two adequate systems in RP2 or even buildcraft.
For Wrath technology, it's more useful than you might think. The wrath igniter itself is an extremely efficient tool for it's ability to smelt or destroy. Often overlooked, it's able to disintegrate ice blocks, or turn cobble into smooth stone. Also, it does not stop at one block, it continues until all blocks of the same type you clicked have been touched with wrath-fire (which becomes normal fire). It does more than make dark iron. Couple that with the Ice-rod the mod has, you can very very quickly remove a lake. As for the wrath lamps, no other mod in the pack creates that much light from a single block. A wrath ligher (1 shard) makes about 20 lamps. Really, all the diamond shard recipe does is create nuggets for diamond. Comes out to about .75 diamonds per wrath lamp. With the two diamond shard recipes taking 8 per (2 cutting heads), the left-over 2 can be used to make 10 lamps, more than you'll probably use.
Finally, there are also two pieces of tech that you didn't touch on, the stamper/packager/maker line of blocks and the armor. The packager is a godsend in any sorting system where XyCraft is involved, however it is equally beneficial with mass snowballs or having a carpenter making ties output to it for fast railbeds. The stamper and maker are a little more complex, but the amount of materials you can store is immense with them. it's nice to be able to store stacks of specific items. Being able to store 512 wax capsules in a single inventory spot can be great. Or as many arrows. Also, for incredibly complicated steve's carts builds, you can slowly build the items without keeping a crafting table occupied forever.
Last, but not least, the armor can be incredibly useful with the mods currently available for it.
Well, almost last, but I'm not even going to try and go down the ceramics rabbit hole.