The full statement from the article was - Rebol and Red, whose open source implementations are still very immature To clarify this… 1) Rebol 2 is a very matur

The full statement from the article was - Rebol and Red, whose open source implementations are still very immature To clarify this… 1) Rebol 2 is a very mature product. But while free to download & use it remains closed source with no long term future. 2) Rebol 3 is an alpha/beta opensource rewrite of Rebol 2. While Rebol 3 isn't has mature as Rebol 2, it is robust and does run about 2 times faster than Rebol 2 and with other significant design & implementation improvements. However it is incomplete and missing some Rebol 2 features. 3) Red could be viewed as "very immature" because the implementation was only started in 2011. However it is looking very promising and I believe the aim is to get to version 1.0 by end of this year.