Do not buy Tekcast machines, they break down constantly and aren't very accurate, you'll think you are casting at 200 RPMs but in reality it can be anywhere from 150-300 RPMs.
There is also a problem with the way the plate is made. The piston pushed up in the center of the plate, but there are no stress bars radiating out on the plate to distribute the pressure so after time the plate will bend upwards in the center which causes the clamping pressure to be uneven and cause flash and fill issues.
Conquest and Conley both make top-loaders that are OK but the repetitive motion of loading, removing the plate, putting it back on then closing the lid can be very tiring and slow.
I've used them at GW and PP and they are all crap.
Nicem machines are the GODS of casting machines. In the 9 years I worked at GW running the mold/casting dept we never had a single minute of downtime due to malfunction or damage to the machine.
Nicem machines are very easy to use, built extremely well and have automated controls even on their single machines.
After you set the pressure, RPMs and time all you have to do is close the lid and the cycle starts automatically and ends automatically. The lid comes up on it's own.
You put the mold in, close the lid (the cycles starts automatically) and pour the metal. The lid opens automatically when the cycle is done, you pull the mold out and repeat.
They are a bit more expensive than the others, but they more than make up for that with the reduced downtime and maintenance. They will also increase your manufacturing speeds considerably if you try to standardize your moldmaking.