The 35mm Samyang is excellent (on my 7D and EOS 3), by most accounts it beats the Canon 35L for a fraction of the price. I haven't got the 24 1.4 yet, it doesn't look as good as the canon 24L, but still, it's cheaper (by a smaller margin than the 35 though).
The 24tse would be nice, I don't think it (or anything else, for that matter) could come up to the level of the TSE24L, but even if the Samyang comes in at less than $1k it'll get a good following.
As to when it will appear, Samyang's facebook said 'mid this year'. Well, 'mid this year' it is, probably at least announced before august, it should be available by the end of the year (frankly, i'd rather trust samyang than canon to give accurate dates for new lenses, given past performance)