The May 06 edition of eWeek has a review of JDeveloper and Peter Coffee who did the review seems to like what he saw.
"It's now even harder to find anything to criticize about JDeveloper, especially since the product's debut price of $995 for unlimited personal use has since fallen to "free" for all developers.
JDeveloper 10g may also be the most quickly learned development environment on the market."
"Overall, we found JDeveloper 10g Release 3 a visually polished, easily learned, highly interoperable and broadly capable tool set for many Java-related tasks."
are some quotes from this review
The full JDeveloper review is here.
I should probably point that Peter reviewed an early access version of JDeveloper about a year ago and he has a more detailed review of it here.