Espressif dveloped the ESP32 and NodeMCU users wait for this more performance offering CPU. The information is rare, yet.
In the NodeMCU repository on Github I found some discussion about the state of development and this nice diagram revealing some internals and peripherals.
It would be nice to hold this device programmed with NodeMCU firmware in hands asap. If you have further information please add it to get a better picture of what we can expect.
I received an interesting link from DIY India Magazine with some more information.
I started the test with a 3 LR6/AA battery pack serving as power source on 2/24/2016 (see 4th IoT Button entry). The test was finalized on 03/04/2016 more or less the same time so I got a run-time for the battery discharge of about 9 days as expected. You can verify the raw data at IFTTT_Maker_btn_pressed and IFTTT_Maker_btn_pressed (1).
This means that the IoT Button can be in operation over a long time as explained in 2nd entry for the IoT Button. Each other IoT Node can work comparable if there are only a few connections to the WLAN router a day.
I have planned to repeat this test scenario to get better proven data from this experiment.