The DGX Spark is probably the best bang for your buck at $4k. It's slower than my 4090 but 128gb of GPU-usable memory is hard to find anywhere else at that price. It being an ARM processor does make it harder to install random AI projects off of GitHub because many niche Python packages don't provide ARM builds (Claude Code usually can figure out how to get things running). But all the popular local AI tools work fine out of the box and PyTorch works great.