Visited this place many times, I think my first time coming here was back in 2014/15.
This library (or part of the building, I'll explain in a bit) is, let's say, split into various areas: Ground floor has Adult Fiction, a Gift Shop, Lecture Theatre, Reception Desk and Children's Fiction. First floor has Young Adult Fiction, Reference/Non-Fiction and a Computer Area. Further upstairs are rooms accessible only by staff/students of the Forum's nearby colleges, so is therefore not part of the Library.
Anyways, the positives: This library is generally very clean (even the toilets are well maintained) and tidy. The gift shop, though pretty small, has a nice charm to it, from soft toys to Southend souvenirs, bags to bookmarks (see photo). And of course being a library, it's so easy being 'lost' in those bookshelves, skimming over each book spine and blurb and finding your next perfect read.
Slight cons (though it can't really be helped): The periodicals (newspapers/magazines) section on the first floor is no longer existent, likely due to the recent pandemic. Also, around midday is when you'll see more college students in the library, which can get noisy at times. So if you want a quiet place to read during then, there's plenty of seating next to the Adult/Gift Shop section where students don't normally frequent, at least from my experience.
Overall, this place is pretty much everything you'd expect from a library. We all need a perfect distraction from our busy lives, and this place pretty much provides that. So why not move away from that TV, phone or whatever and find a book to read for a while?