hardly anyone on here has used an agency, if your case is straight forward there is no need for one, why waste money paying someone else to do what most people on here have done for them self, after all its you that will have to get all the evidence together and meet the criteria (income, accommodation, genuine relationship) not the agency, so most of the work you will have to do yourself anyway - as this will decide on whether visa is granted or not

most on here have not been refused a visa who didn't use an agency, after all why trust something so important with someone else.

but at the end of the day its your choice