Your not going to make much adena with this one, but it does somewhat help you level up a bit.
The drop rate is very low. The usual event prize is GHP's, with a different name, so takes up an additional Inv space. Another thing that seems to be dropping fairly regularly are the 1 hour buff potions. They are not tradeable though, and seem to target Melee classes. So far I have gotten quite a few Might, some Haste (Att. Speed), and some Evasion potions.
On occasion you get a fairly nice 5 hour rune (open when you want, timer goes whether your on our not) I know it does some splashback damage, I don't remember all the other buffs, but it's fairly good. You can also get a Circlet that looks like Antelope Antlers. It allows you to cast Zerk on yourself for 20 mins, once an hour??? Not the greatest. It lasts 5 days.
As for the XP bonus, not bad depending on your server. Problem is you have to be XP'ing in the timeframe that your servers Event Bar fills up, so if your at work/school when it fills, you are SOL. They did make changes to the Prize days in that you should be able to get the event chests all day I believe, assuming your server opens enough seeds.
At the beginning it was the best event ever in the history of L2 :). For some reason, I had no lag/DC issues with the event. All my hunting areas were totally empty. Not even the bot trains were running.
And as I posted, its not going to make anyone rich. It pretty much is a mini boost to XP'ing. And I really do like those Eva Runes :). This entire event, while having the event items up, I have been able to solo the captians area of Varkas/with no down time w/ 1 Tag along low level SE. Before the event, I had a hard enough time keeping up a fast kill rate in the Soldiers area.
Also, being online during the XP bonus time is sweet as well.