Budget is what got me into those since I could not afford THK rails.
For my next build I plan to try Linear Carriage on Cold Rolled Steel (
CNCRouterParts.com). I doubt my budget will increase much by the time I build since I'm already anxious to get started. This style looks like it would be a lot more ridged and could be beefed up easily or even expanded down the road without needing to replace much. They are still very budget friendly and would be easier to do maintenance on. There are several DIY builds using them and I'm no expert so do some searching, there is tons of great info and help on this forum. Take a peak at
THIS , it is one of my favorite builds using them.