I had a Mango singlespeed, thought it was pretty good for the money albeit heavy with very unforgiving wheels & tyres, had it stolen.
Today ive just taken delivery of a PlanetX Holdsworth La Quelda singlespeed, out of the box its quite pretty with a retro charm about it.
Lighter than the Mango and definitely more responsive. Compact drop bars are comfy although the Tektro brake hoods are a tad hard on the hands.
I went for a 42/18 gear which may prove to be a little low but need to have a few rides yet to be sure, not a big problem to alter though.
Wheels are heavy of course, but feel quicker to spin up than the Mango versions, tyres aren’t great & feel a bit hard, again not a big thing to change.
Brakes are OK for the money but may need better pads for wet weather.

All in all I’d say that considering the two bikes are similarly priced, the Holdsworth is a far better bike for the money – looking forward to my commute now!