Nice neat build. Love the colorful chassis choices. I am a big fan of whimsical!
Following my first taste of Crack then Speedball, I built an Eros 2, which is a lot more components, four tubes, and three PC boards, but not really harder, just more. I followed it with a Moreplay, which is a simpler circuit than the Eros, two tubes, no PC boards, but does have a lot of slightly confusing interconnect soldering with the input selector, balance and volume. So both the Eros and Moreplay are more complex than the Crack & Speedball, not harder, just more. I'm in the midst of a heavily modified Stereomour build, still prepping the chassis, not far into it yet. I recommend picking the component you expect to get the most use from next.
Crack vs Crack & Speedball impressions: I felt the naked Crack was a bit warmer, maybe a bit lusher sounding. Speedball tightened it up, not as much of a lush, more sober sounding;). I miss the lush a bit, but also appreciate the accurate sober sounding speedball. Exquisitely pairs with HD650's.