So why Synthetic Phonics – what's wrong with other methods of teaching reading?

I have found that the multi-cueing methods which are recommended by our own infant curriculum and which amount to guessing using picture, context and/or initial sound cues, and which are also encapsulated in the Reading Recovery method, to be far less effective when teaching both beginner readers and older strugglers than teaching according to the synthetic phonics teaching principles.
My view of SP as the most effective method to teach beginner reading is also supported by the Rose review of beginning reading
http://www.standards.dfes.gov.uk/phonics/report.pdf
which states that
‘synthetic’phonics
is the form of systematic phonic work
that offers the vast majority of beginners
the best route to becoming skilled
readers.Among other strengths, this is
because it teaches children directly
what they need to know, i.e. the
principles set out below,whereas other
approaches, such as ‘analytic’ phonics,expect children to deduce them.
Following this report the British governments latest guidance no longer recommends the multi-cueing methods but rather a systematic synthetic phonic approach based on the ‘simple view of reading’ (see above link for details).
Consequently there is ongoing controversy at the British governments unusual choice of RR as an early intervention strategy, given that its underlying multi-cueing teaching principles are the very principles which the Rose Report makes clear are no longer acceptable practice for beginning teaching or remediating reading difficulties!
While I have no personal experience of using RR, I have had many years of mixed method (multi-cueing) teaching prior to changing to teaching according to the SP principles and so I feel qualified to compare the two methods.
The benefits of SP,for potential strugglers in particular, are quite amazing- no longer do their eyes dart all over the page for clues, no longer do they become confused about which clue to use or guess wildly in the absence of clues, no longer do I sit next to a weaker child, checking their words/reading while willing them to make the correct ‘guess’so I can praise them.
Now they simply and confidently sound out all through a word (spelt using letter/sound correspondences taught to date so there’s no need for any guessing) and blend to read.
They segment a spoken word into sounds and map the correct graphemes onto the sounds to spell.
They are adept at tweaking tricky words- sounding out the regular parts and tweaking the tricky parts. Their bank of decodable words expands each time they are explicitly taught a new letter(s)/sound correspondence.
They are explicitly and progressively taught the code knowledge and trained in the skills of blending and segmenting, putting the code knowledge to immediate use.
Should they encounter or require an ‘as yet untaught’ letter/sound correspondence, I simply point out to them where it fits into our alphabetic code chart, supply the required phoneme or grapheme, (doing a little incidental phonic work as I do so) while reassuring them that we will be learning more about that alternative in time as we work systematically through the code from simple to complex.
While RR does include some phonics, from what I can gather it is not explicitly and systematically taught but is rather dealt with incidentally.
The inclusion of multi cueing and the lack of explicit systematic teaching of the alphabetic code concerns me.
This concern is compounded by articles I have read suggesting that there is growing nternational concern about the efficacy of the RR programme and that more and more people are beginning to abandon the method for the synthetic phonics teaching principles instead.
http://www.rrf.org.uk/newsletter.php?n_ID=186
http://rrf.org.uk/messageforum/viewtopic.php?t=3258&start=0