I used a few lines in the `single-product-reviews.php` woocommerce template to unhook jetpack on only product pages. Otherwise, it overrides the review form. Just calling the `Jetpack_Comments` class and removing those actions before the `comment_form()` was enough to selectively deactivate 'em. Note: your `single-product-reviews.php` might be i…

single-product-reviews-excerpt.php

$jp = new Jetpack_Comments;

remove_action('comment_form_before', array($jp, 'comment_form_before'));
remove_action('comment_form_after', array($jp, 'comment_form_after'));`
 
comment_form( apply_filters( 'woocommerce_product_review_comment_form_args', $comment_form ) );

Newbie question! Where should I put in single-product-reviews.php template???

This should give you the basics of where it ought to go: http://docs.woothemes.com/document/template-structure/

/themedir/woocommerce/single-product-reviews.php is where mine lives.