Well i have seen MANY pakistani applicants on this forum n personally who applied through consultant but still got delayed. Consultants can only help you till PER, after that you really don't need one! CIC encourages ppl to apply on their own. The notion that London Visa Office treats applicants based on their "Representative form" is just absurd. Any delay post PER is mostly because of background checks, which is unique for every applicant.
I guess following types of applicants need consultants:
1. Rich, who dont care to spend some extra bucks.
2. Busy, no tume to read.
3. Previously refused case or some complexity.
Otherwise you dont need one. This forum is far better than any consultant
senior guys here are very knowledgeable (apart frm few) and they are ready to guide you.
ABSOLUTELY AND +1 FOR YOU