as a tutor i checked this out and ...i think the 2nd site "All guitar chords" is way better since unless i missed it the chord formula's were not shown in the 1st site ....... all guitar actually explained the chord ..not in it's notes but by it's formula........
Name: Major 13 #11 chord
Symbols: maj13(#11), maj7(13,#11), maj9(#11,13)
Steps: 1-3-5-7-9-#11-13
Recommended scales:
Lydian scale
the 'steps" info is the most important for any guitarist to memorise 1-3-5-7-9-#11-13 this is the chords formula but ussually written in roman numerals ........... I III V VII IX #XI XIII AND THIS OBVIOUSLY APPLIES TO THE NOTES ON THE MAJOR SCALE ( the DO RE ME SCALE )
so yeah chord dictionaries like this are great but memorizing the chord formula's is what is more important ........do this and i assure you any alteration is dead easy .... learn it once ( there is a method and a few rules) and you'll be able to play any chord no matter what the alterations anywhere on the neck...........
so speak to your nearest tutor a lesson in chord formula's should take 40 min and worth every cent cos once you understand how the formula's work...... the most complex chord you find in music can be easily worked out .... and in any voicing too.......... there is a method ? which all tutors should be able to teach you .....if not they should not be teaching .... then chords will never scare you ever again
but yeah the 2nd site has more info and better laid out ...or let me say has the "steps" which i could not find on 1st site just the note names........ cos knowing the steps (formula) is the secret .......