Fully automating a sugar cane > biomass > biofuel > boiler process is one of things I like doing most. It's also one of the first things I try to accomplish when I start out, just because it gives a lot of satisfaction when you finally get it working.
I will safely disagree with you here, after having fully automated a 120y-ish high tower around 20x20 in size. It wasn't too bad with turtles, but it was not something I'd consider a logical first automation step, whereas Steve's Cart is much easier to setup and deal with as such, I've found.
Still, a massive sugarcane tower is a lot of fun the first time you do it.
And now I have 4 boilers, complete overkill. 2 on biofuel, 2 on charcoal. I will be adding 2 more on fuel when I get my distilled bee production up and running.
I was running two HP36 off of six layers (with ten layers set up, but the last four disabled because of too much sugarcane), and I went from around 1,000 buckets of biofuel (I turned the entire system off, so that went down a bit from my stockpile) to a full 10,100 buckets (or whatever the full 9x8x9 railcraft tank holds) in less than a day, roughly.
It's nice, but having to baby sit the system whilst getting there isn't worth it in the short term, and the long term is par with the Steve's Cart tree farm.
But you cannot make a massive tower for Steve's Cart tree farms that'd look anywhere near as sweet as sugarcane: