We use the mPop 2in1 cash drawer and printer. I don’t really care for it. We have the same issues with it that you mentioned. Another problem is that because of the Bluetooth connection, we have to leave the iPad connected to it plugged in at all times. Otherwise the battery dies.
Perhaps the biggest annoyance however, is that we can only print receipts from that iPad. We use up to 6 different devices in our tasting room on a busy day. We have to process a transaction on one device and then pull the order up in the order manager on the connected tablet in order to print a receipt.