I too have read Agatha Christie a lot. Her works are quite intriguing,
but when it somes to characters, even her own Miss Marple and Tom and
Tuppence, the secret adversary pair are better than Hercule Poirot.
And he's no competition for Holmes. He simply does not appeal to one's
senses as a detective, but maybe he's a little too showy as you said.
When it comes to the kind of thinking and theorising that is needed
for any detective, fictional or real life, Holmes possesses in
abundance. Also he seems to have uncanny knowledge of many things such
as chemicals, tobacco stains and ash, and music. These make him a lot
more appealing to my senses and those of may people the world over.
So my verdict: Holmes wins hands down over all of Christie's
characters combined.