I counted 5000 drops with an approximate 200 MF and repeated with an approximate 300 MF. Nearly the same drop rate of rares and the higher MF had a lower drop rate of exotic and ascended.
Rares 200 MF: 72
Rares 300 MF: 77
Exotic 200 MF: 9
Exotic 300 MF: 5
Ascended 200 MF: 2 (both rings)
Ascended 300 MF: 0
Magic Find does not appear to influence rarity on rare, exotic or ascended at least in WvW for my small sample set. I did not count blues and greens separately (would have taken too long). While it is difficult to gauge I don’t think it speeds up the drop rate in WvW either but that is very difficult to measure.
My method was pretty simple. I only played WvW on my main. I banked all chests from the Reward Track so they didn’t count but opened all bags from Supervisors. I avoided all banners and MF buffs. I salvaged all blues and greens counting them as I went. I vendored all rares and exotics. Banked all ascended. Did that for about 5000 drops then popped a few Birthday gifts and repeated.
Sarcasm For Hire [SFH]
“Youre lips are movin and youre complaining about something thats wingeing.”