When I was looking for a fermenter I was close to getting the small Spike, but ended up getting the half barrel SS Brewtech unitank. Awesome piece of equipment, but I am regretting the size. It is 15.5 gallons, and I can't do a 5 gallon batch because the thermowell sits at about the 7 gallon mark. This is important for temperature control. I keep it in my shop and need to be able to heat or cool to maintain desired temps. Also need at least 10 gallons to crash cool.
I just have to do larger batches, so I'm looking into a stainless steel 20 gal mash tun.