Having played a bunch of Metallurgy, the intended progression is that you always start with Stone tech machines, and then upgrade each individual block up through the metal progress. Stone->Copper->Bronze->Iron->Steel for all the base machines. You use the nether metal progression for the lava smelter, and the precious metal progression for the Metallurgy chests (Wood->Brass->Silver->Gold->Electrum->Platinum).
You need a copper crusher to make a bronze crusher anyways, unless they changed the recipe. So if you are set on the Metallurgy machines, the above shortcuts won't help as much. I think a Pulverizer uses 400 RF per ore, and gets 16K RF per coal in a dynamo, so I believe the TE machine is more efficient. It can also process more types of things then just metal (which the crusher can't do yet, again unless it's been updated, but I do believe they were planning on adding that in the next update).
Edit: On the plus side for Metallurgy, the Steel Furnace easily rivals a Triple Thaumcraft Bellowed Furnace for fuel efficiency and speed. And the Gold/Platinum chests hold a massive amount of items, again easily rivaling the best chests from the Iron Chests mod (which might not be in Horizons? I forget).
Edit, the second, Duke of Equipment: If you also have the fantasy metals, and can eventually get Celengil (it's Orichalcum + Platinum) it's freaking amazeballs for making Tools/Armor out of. But being Orichalcum it's rare to find, and you'll need a ... Mythril pick to get it, which needs a Steel pick to mine that. Everything in Metallurgy is based around the tiering of the metals.