We had issues with Simcom modem chips as well as Telit. The newer Simcom chips are better and quite competitive, pre Sim800 it was riddled with bugs. If then Telit was an option, now it isn't because it's considerably more expensive and the IoT market is very competitive. 3G chips were the worst pricewise because they had to include royalties to Qualcomm, that's why most chipmakers pushed for 4G.

The ESP family is absolutely amazing in terms of price and features, not so much efficeincy wise. It would have been great if RTOS support was better. The ESP-IDF is based on FreeRTOS, NuttX has some preliminary support, RiotOS doesn't do FPU, BT, crypto acceleration and uses one core only. NodeMCU is maker/hobby garde, not an OS and so is Arduino. To be fair, the whole ESP chip family is rather hobby grade but if it works and you're not power constrained or you use it as a secondary MCU and put it to sleep, it should be fine.