The Wanhao is my third 3D printer. It is also the cheapest and by far the best performer. If you are looking to get a 3D printer, my recommendation would be to buy the updated replacement model, the <a=http://wanhaousa.com/products/duplicator-i3-plus-steel-frame>Duplicator I3 Plus. This currently costs $399. You can still buy my model on closeout for $80 less but the upgrades are definitely worth having.
Don't expect this, or any 3D printer to be perfectly plug and play though. People have found that to get the most out of $3,000 printers, they need to make some mods. These are the ones I have made
All told, these updates add up to $143 excluding the Simplify3D software which you should consider getting for any 3D printer. If you are starting from a Plus, you don't need the upgrade kit and so your cost is $118.
I use Simplify3D for both slicing and driving the printer. Unfortunately, there is a bug in the Wanhao firmware that means this is likely to fail randomly unless you remove the Auto-Reset jumper on the Melzi board.
One of the first mods I did was to print and install the Z-Brace and extensions by Aaza. There are many variations of this mod and I have only tried this one. But it seems like the one to go for. It gives a slight boost to the Z-axis clearance.
The purpose of the Z-brace is to stiffen the frame up and prevent the Z-axis flexing while printing. Big triangles are stiffer than small ones.
The original i3 build plate leveling thumbscrews are total junk. So I printed up some plastic replacements. I am currently waiting on the upgrade pack for the i3 plus that has proper metal leveling wheels.
I bought two glass build plates which was a good idea but from separate vendors which was not. Having multiple build plates saves a lot of time as you can simply swap one out for the other when changing over builds. Or rather it would do if the plates were exactly the same height which it turns out isn't the case. Mine are off by 0.04mm which isn't significant till you realize it is two layers.
I bought a pot of 3Deez which works really well at sticking parts to the bed and it releases easily in water. Lots of people have asked if this is just PVA adhesive (Elmer's white glue) with some dye. I don't know. But what I do know is that the white glue seems to work just as well and costs 10% of the cost. The key seems to be the method of preparing the bed (three thin layers applied with a foam bush).
I use a checkerboard of heat transfer pads. This provides better thermal contact between the bed and the glass than just placing it.
At the moment, I am using bulldog clips to fasten the plate to the bed. I would like something that does not foul the hot end so easily.
The only part of my print head that isn't replaced is the motor. The Wanhao print head has serious problems at both the extruder and the hot end. Now to be fair, it does not have anywhere near as many problems as my MendelMax2/3 did. The print assembly on that weighs 2Kg which is utterly insane and coupled with the bad choice of X axis a major cause of the consistently bad results the printer gives.
I upgraded the hot end first, installing the Micro Swiss hot end and cooler block and the hobbed gear. That solved most of my problems for a while till I started having a problem with skipped layers which seems to have been cured by replacing the lever arm and mount with all metal versions, again by Micro Swiss.
The main ongoing problem is the difficulty of leveling the bed. If it is out by a fraction in either direction, the print just doesn't stick. I am hoping that the better thumbwheels on order will fix this.
The fan is horribly noisy and should be replaced before the worn bearings force the issue.