Captouch describes HE5LE pretty good what I hear and even Im not familiar with HE500 Im sure I wouldnt like it so much.
Regarding powering HE5LE I could be annoying but Black Pearl amp gives great result with it. It gives about 1.3W at the output but its really enough IMO unless you like just little more coloured sound or more forgiving amp with weaker source scenraio. Source is really also very important here for such revealing cans. If you have setup without much weakness I just cant imagine these cans can be too bright. Surprisingly I find it similiar to Beyers DT880 in terms of overall balance but all frequencies are just more natural and better.