Will be upgrading to a shop press setup aswell in the near future
Is it worth it to go over DHgate quality on plates and pids?
Short answer: Yes it is worth it.
Long answer: DHGate is cheap for a reason. I dont want to run across breaking any rules here, but you do pay for what you get. The plates as a rule are machined just enough to pass inspection, there can be variations on the 'flatness' of the pressing surface. which can lead to uneven pressing. ( even a small variation can make a difference at high pressure.)
The pid controllers they use, you can buy on ebay for $9.99 or less. They have the thermocouples built right into the heater cylinders. This gives the temperature of the heating cylinder, NOT the temperature of the plates. This can be out as much as 50-100 degrees F.
If you want to buy an all-in-one, be prepared to spend around $2,000 - $5,000 USD and up to $10,000 for anything worthwhile. You need a min of (IMO) of 1000 psi at the plates. For 5x3 plates this translates into 8 tons of downward force. (1066 psi over the entire 15 sq in of the plates), now granted you would most likely be using a 4x2 bag with 5x3 plates. This means that you only need around 5-7 tons of downward force to get the PSI needed on those bags. You now have a surface area of 8 sq in.
In the end it really does matter. You can pay 250 for a set of plates, but you really do get what you pay for and I can say with some confidence that you may not be happy with what you get. Customer service is somewhere halfway around the world. Warranties are minimalistic and odds are..they are less than 90 days from purchase..or not at all.
I have been building and selling rosin plate kits now for over a year..some of the horror stories customers tell me about their overseas plate buys are amazingly bad. Most are just regular bad..but still bad enough for them to buy a second set of plates from a reputable seller.
You really do get what you pay for.
EDIT: added "I have been building and"