Word for someone who is extremely up-to-date with the latest facts (news or research)

I seek a word for one who is up-to-date, enlightened, and extremely well informed about the latest developments or research in a particular field.

An example is a person who complains about a recent encyclopedic book publication, criticising it for being out-of-date despite its recent publication date. I want to be somewhat ironic and say something about his or her obsession with "up-to-date-ness" and his failure to appreciate this truly magnificent book. Any suggestions?

How about a little French (which I think is a great language for irony), call him au courant?

This person is not just leading edge, but bleeding edge.

Edit: If you want a term that is less colloquial, you can say that this person is at the forefront of technology. (You did say you wanted a word with an ironic edge; but irony is often in the delivery...)

Someone who is on the bleeding edge deals with unreliable, untested, and (with regard to tools) largely unused tools, products and information. With that in mind, there are a few words and phrases you can use that focus on particular aspects of his up-to-date-ness.

Prophetically Informed adjective

Prophetically: predictive; presageful or portentous; ominous

This is a phrase you could use ironically. More of the information in the encyclopedia will be relevant in 6 months than of the information that he has, due to the fact that only a portion of bleeding edge information, tools, and products withstand the rigors of time. Some of the things he is focused on will make it, though - making him feel like a prophet simply because he knew that "Product X was so much better than the current industry standard, Product Y." You could also call him a "<Field> Prophet."

Consultant noun

a person who gives professional or expert advice

Whether he is or is not a consultant is irrelevant. Consultants in a given field stay up-to-date on the tools, products, and information in their field.

Scientist of <Field> noun

This phrase is on the fact that he is relying on early experimental data. It does not necessarily convey the idea of unreliability, though.

Bleeding Edge Professional or Bleeding Edge <Field> Professional noun

This phrase conveys the idea of bleeding edge in a noun. It insinuates that he is not focused on established technologies, but just those that are bleeding edge.

Early Adopter noun

This phrase could be used dismissively, to focus on the fact that he has adopted a tool or product before the industry or many others have. It also conveys the idea of unreliability. The use of the word "early" explicitly makes it clear that it may be too soon for someone to be concerned about these technologies.

Alpha (or Beta) Tester noun

This phrase, used as hyperbole, indicates that he is using information, products, or tools that are barely tested at all, and also strongly conveys the idea of unreliability.

Ultramodern adjective

very advanced in ideas, design, or techniques.

Vogue noun

something in fashion, as at a particular time

This word describes what he is familiar with, rather than what he is.

A neutral term could be avant-garde.

Avant-garde represents a pushing of the boundaries of what is accepted as the norm or the status quo, primarily in the cultural realm (wikipedia)

If you want irony and a little wordplay is fine, you could say someone is upper-to-date.

I think the comparative works even better than the superlative, because it conveys an attitude of always opposing against something/someone else. Like saying that someone always knows better can be ironic, because it means that that he really is just cocky and annoying. But if you say "mother always knows best" it means you trust her, without any irony.