Great station! Excellent connections on the Metropolitan Line connecting you to Aldgate, Chesham, Amersham, Watford and Uxbridge. There are also fast trains (skipping Wembley Park, Preston Road, Northwick Park, North Harrow, Pinner, Northwood Hills and Northwood) and Semi fast trains (skipping Wembley Park, Preston Road and Northwick Park) during the morning and evening peaks which is very good as it feels like I'm on an endless stream getting from Amersham to Aldgate! There is Chiltern Railways which connects you to the wider Buckinghamshire. The Station is very clean and hygienic. There is police presence so there is a lot of safety. However, there are too many pigeons flying around! I would give 5 stars but the reason I'm giving 4 stard is that sometimes the boards on the Southbound platforms are inaccurate. For example, this morning it said that there was only Metropolitan Lines to Baker Street coming and it didn't tell me when the Aldgate trains coming. So I got onto the Baker Street train and a Semi fast train to Aldgate comes flying past! I should have checked my phone instead. So I missed a Semi Fast train sadly. Apart from that, Harrow on the Hill Station is excellent. I also believe that they should work on the step free access to the station as other reviewers have said this is being delayed.