Lots of people deride the F28. They are almost invariably those who have never flown it. (just as I deride the Robbo, having never flown it)
They are good, well made, well designed aircraft. They are very pleasant indeed to fly, and although the "A" model is not exactly overpowered especially 3 up it is adequate - just. Still, it's good practice. The 28C has lots more power due to the turbocharger - but you pay more. Autorotation is good, relatively high inertia c/f a robbo. Nice and forgiving. Instrumentation is basic in most "A"s, but what do you want an AH for in a VFR machine? And it looks like a helicopter, not an airfix kit. And if you want to see what they are really capable of doing, watch a video of a Dennis Kenyon display. You won't believe your eyes!
Robinson. Pah!
Maintenance.
Engineers hate them. They were designed to fly, not to be maintained easily or cheaply. I remember rotor tracking was a pain and was needed frequently, but a smooth-flying Enstrom is a thing of joy. A battery change involved a ridiculous amount of dismantling of structure to achieve. You'll need to find a tame Enstrom specialist engineer to look after it.
There are plenty of cheap dogs around though, so seek an Enstrom expert's advice and buy one that is known to him as a good one.
You'll love it!