Now you see ezComments version 0.02 working side-by-side with the other plugin here. I think mine is slightly better.
I used a workaround to tell trackback/pingback, i.e. if it's not a comment the comment_author_email field is empty. This has assumed that site owner would have checked the options>discussion>'comment author must fill out name and e-mail' optioned in admin.
The comment_style in database returns nothing that I could use, simply don't know why.
Another characteristic is that if it's a trackback/pingback the comment content is wrapped by [...]. (PS: now have this removed for a nicer display) I could possibly go further by letting user to have a choice to separately list track/pingback and comment. (PS: done, now they are grouped)