Keith Dillon has already said much of what needs be said about this score. Ideally I'd have given it a 4.5 or even only 4 stars due to 2 faults with those initial Schott editions - except Mr. Dillon has already beaten me to it (yet his review is warmer...)! Consequently, I'll raise my mark to counter-balance given the low price. [Getting the current Schott Complete-Wagner Works Edition, which does follow proper conventions, surely would cost a king's ransom...]
The faults are: 1) Inconsistency about ordering of instruments and/or voices per system; 2) Slightly less than ideal clarity in printing due to the styles/fonts of engraving then used.
Regarding the first point: it was a period of transition from an initial time where other instruments and voices would be inserted between the upper strings (violins, violas) and the low ones (which still were notated à la "Continuo" function long after that style of composition had died) versus today's systematisation where everything is grouped by order of class of instruments and/or voices (woodwinds, brass, percussion, harps, keyboards, solo-voices, choral-voices, strings - going from top to bottom in a system). That full-transition hadn't quite finished yet (it so did around 1910 with Peters' editions of the Wagner operas - "Tristan und Isolde" used the old order Wagner used, whereas "Die Walküre" and "Parsifal" were in the new order - other composers like Richard Strauss were already established however with the new order...).
Also, as an extra challenge, tenor voices (in this case: Siegfried, Mime) are notated using the tenor clef - not that I mind; however, others might.
Anyway, those are minor quibbles - in compensation one knows that he's dealing with very reliable scores proofed (if I recall correctly) by Wagner himself, with few mistakes if any - all of which can be corrected by listening to appropriate recordings. Definitely recommended!