Ours currently has a normal W, although it is design for LaB6 operation. The W is nice and stable and has been operating for several months without a clean, however I need a bit more brightness. Dr. K. Moulding. Materials Characterisation and Preparation Facility Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Pointed filaments have less than half the life, on average, when compared with standard filaments.
They are more expensive and cause more downtime. They were one of the few means to achieve that extra little brightness 20 years ago. LaB6 give more brightness and reduce downtime a great deal. In the end, they are economical. I would try to improve the vacuum.