I've been reading Tintin since I could barely read, taking them out of my local library as a natural progression from the picture book section. Before I was confident enough to follow the large balloons of long words that fill Asterix, I could appreciate the clearly drawn actions and reactions of Tintin, starting with 'Snowy doesn't look where he's going and walks into a dustbin' and working gradually up the layers of sophistication. Comprehension of the plots came later, and a really deep appreciation only arrived when I learned more about the life and times of Hergé.
I came round to Asterix in due course and borrowed his adventures from the library too, even ploughing through my dad's French copies and one in Latin given to me by kowarth. But Tintin was there first and it was the Tintin books I began to collect privately, many as birthday presents from my grandma and grandpa.
The scope of Asterix's world is limited. All the Asterix books have the same structure: a quest, some anachronistic jokes, Romans get thumped, then there's a big feast. Tintin's world constantly expands and deepens, from the simplistic USA and USSR of the early books to the fantastic landscape of Tibet and the surface of the Moon.
I have Tintin on my wall; I wouldn't put Asterix up there. The artwork of Uderzo is lively and funny, but also a touch grotesque. I can close my eyes and recall just about any panel from any Tintin book, while Asterix is more about repeated images: Obelix toting a menhir, Asterix's toes leaving the ground as he drinks the magic potion, any character cocking his head and tapping his temple.
The names in Asterix are brilliant, of course, but remember that Tintin has funny names too, even if Getafix and Fulliautomatix are more obviously hilarious than the Maharajah of Gaipajama.
Finally, clinchingly, Snowy > Dogmatix. Obelix's little dog doesn't really do much, whereas Snowy is always in the thick of the action: getting drunk, chasing cats, occasionally performing feats of intelligence or selfless bravery, and providing wry commentary from ankle level.
So, over to you.