Oh god I dealt with this recently while training my own 1B model.

Runpod - mostly okay, except sometimes instances get dropped on smaller ones. Prices float around 3.20 mostly for H100s. Cheaper ones exist but are PCIe. Best DX out of the bunch honestly (well, AX, as my agent was the one dealing with it). Didn't end up doing the 1B run on it, but did 100M+ runs and some minor experimental ones. Great for agentic exploration, "RSI", minor training loops and research.

Vast.ai - a bit pricier for the same H100s and it didn't have any clusters. So I could at best split my workload across 2-3 different H100s and spend time syncing. Not worth it.

Akash - since I'm trying to stay in a reasonable budget, I decided to try Akash, which was the worst experience out of all. Cards would be "available" but would never respond to your request. After trying to contact support via Discord, I got dozens of fake support accounts adding me to scam discords and asking for my wallet key. Support answered after a while, but without a real answer.

Mithril.ai - Ended up using this one, while it seems quite startupy, the actual offer is nice, it was easy to get going and they offer quite cheap H100s, offering singles and clusters.

Tbh while Skypilot is great, the marketplace fragmentation is leaving room open for a openrouter-like compute provider.