I run a medium sized gardening company and am currently looking into replacing our fleet of hayters that we have used for years with either the current model of Hayter 48/56 or Lawnflight 553 HRS Pro.
So far it appears the Lawnflights are pretty good, having a Honda engine on a cutting width between the Hayter 48 and 56 at 53cm and a hydrostatic drive i.e.shaft driven rather than belt driven like the Hayters.
I am not currently considering the Honda as the Lawnflights are basicaly the same but cheaper - The Lawnflight deck was originaly a Honda design the Honda's are slightly more expensive as unfortunately you are paying for the name.
Parts are probably a bit cheaper for the Hayters and the Hayters are also cheaper to buy, but I have been advised not to spend the extra for the pro Hayter version by my local mechanic.This is because to pro ones have a set speed of 3mph where the standard ones have a variable speed with a maximun of 3.5mph, although the variable speed adjuster can break, it doesnt matter if you fix it at the faster speed and the additional cost is not really worth it for the extras you get, the standard models are still very strong and good machinesl.
The bigest concern with the Lawnflights is the gearbox, which can get damaged and wear out.These are much more expensive to replace than the Hayter ones at about 6x the cost, but if you are careful to avoid dropping the roller assembly onto hard ground, as it will push the drive shaft into the gear box and avoid as much as possible running the roller over hard ground (concrete etc) it should last a considerable time.
Also you can purchase parts for the Lawnflight gearbox and hopefully avoid having the replace the whole thing.
The other point to consider is the weight as the Lawnflight is a much heavier machine to move around and use compared to the Hayter.
Both Hayters and Lawnflights are very well built and a lot of the problems that the Hayters had when the current design was orriginaly released have been fixed.
I dont think you will go far which ever one you choose, perhaps see if you can try them out before hand as it may help you make your final decision.
Unfortunately I have tried both and I am still currently undecided on which model to purchase!