Hi all - and a happy new year to all of You

I'm in the planning to build a CNC Mill from scratch and need your opinions about my choise of rails.
I have ended up with a gantry mill, with moving gantry. X, Y and Z rails would be 50-60cm each, and want to do milling in wood, aluminium and soft steel.

I have been looking at THK and IKO linear rails, but they seem somewhat pricey for my budget.

Lattely i have found these supported rails, sold as a complete set for 3 axis (rails, ballscrew and supports).

cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&item=250480359788

But im in doubt about if they are strong enough to withstand the forces that would be applied to them?

Anyone had any experience with these?

Thanks in advance

Jesper