Hi
I'm French and new to the forum.
I've read you have some difficulties to compare the Sapphire and the Frontier.
I do not own them myself, but I know a test that has been done to compare them.
Obviously it's in French but google can translate it for you
I can translate myself if you wish so.
The conclusion of the review is that the sapphire has a better neutrality of the colours while the frontier is a bit yellowish.
(According to the tester, it's a nice effect since it heats up the picture - maybe that's why some of you may like the Frontier better).
The second difference is about the acutance being better on the Sapphire.
Other points are the size and weight - the Sapphire being smaller and lighter.
He rates them at exactly the same level as far as price/quality ratio is concerned.
http://www.topoptics.biz/Technique/Bras-de-fer/HawkeFrontED1043_vs_SapphireED1042.htm
Hope you will find this helpful.
Kindly,