I am not sticking my head in a hornest nest but basically:
1. fpweb is fully written in Pascal and well maintained by the FPC development team. That means it has an advantage if you have a good understanding of Pascal and it is easier to debug from Lazarus.
2. other frameworks may be just as good.
3. I would also have a look at pas2js and the frameworks that it supports..
Note that I almost exclusively use fpweb as a basis for my own needs, but I often use a different framework for commercial applications (often customer requirement under the motto: industry standards) and often interface with PHP and JavaScript code. Sometimes even interface with Java, using the FPC Java compiler. (Yes, fpc can generate Java byte code, interchangable with a Java program, or the other way around, can use Java modules/classes in an fpc main program.)
Pascal alternatives are also Indy and Synapse.
All have different requirements. You must also distinguish between Visual parts and your low-level client and server parts, Often you will mix and match for what is needed.