LEI 6.5 Virtual Documents - Scalable?

Is the LEI Virtual Documents concept applicable to an environment where performance is a major consideration?

We have certain applications that are built exclusively on Domino. We are planning to open them out to a much bigger group of users.

Would keeping the data in Notes be a much safer bet than using and RDBMS and real-time access via LEI for performance? (Assuming Performance is more of a consideration than integration of enterprise data.)

In other words, does the separation of data in RDBMS and introduction of LEI acitivites to fetch data result in a performance hit for database reads/writes?

Some NSFS might potentially contain a few 100,000 records. Should we even be thinking Notes/LEI in this case?

(Also posted in EI forum)