Many types of conservatory gutters have a bad reputation for being unreliable and prone to problems. The gutters are usually designed to hang from thin internal brackets which are much weaker than external fascia brackets. Furthermore, the clips (part of the gutter joints) which clamp the conservatory gutter joints to the gutter go brittle over time and eventually break off removing its ability to compress the seal and make water tight.
To top this off, many conservatory gutter parts are either obsolete, difficult to get hold of, or are very expensive compared to standard guttering that you would find on a house. Replacing the gutters for a better, more adaptable system often makes sense.