Подскажите, пожалуйста, есть ли разница в последовательности слов rather is / is rather в следующем предложении:

The pianist does not always adhere to the dynamics, the composer’s tempo notations, but rather is guided by his own feelings in choosing the climax moments.

Гугление показывает, что возможны оба положения. Я особой разницы не чувствую, но больше склоняюсь, что rather перед is звучит лучше.

http://books.google.com/ngrams/graph?content=but+rather+is+guided,but+is+rather+guided&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1;,but rather is guided;,c0

http://www.google.ru/search?newwindow=1&biw=1280&bih=912&tbm=bks&ei=tT2MW8SSCdCKmgXe6IXICw&q="but+is+rather+guided"+site:uk&oq="but+is+rather+guided"+site:uk&gs_l=psy-ab.3...2635.9510.0.10834.8.8.0.0.0.0.137.587.7j1.8.0....0...1c.1.64.psy-ab..0.0.0....0.OGn45AUFG6c

a)  not ...... but rather, ...... means that one thing isn't true but a different thing is true. When used like this it means 'instead' or 'more accurately'.
Examples:
* 'The question isn't whether the election will take place, but rather, when it will take place'
* 'The problem isn't their lack of funding, but rather, their lack of planning'

b)  is rather guided, in theory, just means 'is somewhat guided'.
Similarly,
* 'rather annoyed' = 'quite annoyed'
* 'rather late' = 'somewhat late'.
However, very few people would use 'is rather ......' with a participle such as 'guided'; instead they'd probably say something like 'is guided somewhat' or 'is guided to some degree'.

In the example you quote, a) above applies and 'rather' means 'instead'.

https://www.google.ru/search?q=%22but+is+rather+guided%22&newwindow=1&source=lnms&tbm=bks&sa=X&ved=0ahUKEwjb4eGKkZ3dAhUC2CwKHY3uDOEQ_AUIDygA&biw=1421&bih=741

И более 1200 в общем списке.

С rather is - 678 в книгах и более 30 тыс. в общем. То есть, с rather вначале - гораздо более частотно, но с is тоже допустимо.

Феномен, что получаются разные результаты из разных локаций, тут со мной уже случался и обсуждался (тогда это было с Шумовым).

http://www.google.ru/search?q="but+rather+is+guided"&newwindow=1&tbm=bks&ei=j0CMW7L9NcqfsgHLjaGYAQ&start=10&sa=N&biw=1280&bih=912&dpr=1

Я поэтому тут и спросил, у живых людей, в надежде, что могут откликнуться и носители, и действительно, John дал исчерпывающий ответ.

In each of those examples on Page 1 of your link, the author's using 'but is rather ......' as a variant of the 'but, rather, is ......' in my para a) above.

It's not poor English, but the author has complicated matters slightly and created ambiguity by:
i) putting 'is' before 'rather' instead of after it; and
ii) omitting the commas,
so that at first sight his 'but is rather' looks like 'but is somewhat' (see my para b) above).

Most people in this situation would write 'but, rather, is guided' – see this link:
http://www.google.co.uk/search?as_q="but+rather+is+guided"&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=&as_qdr=all&as_sitesearch=&as_occt=any&safe=images&as_filetype=&as_rights=

Note that 'but is rather guided' has 265 Google hits, whereas 'but, rather, is guided' has 36,400 hits. So 'but, rather, is guided' is the way roughly 99% of people would write it.