Trustfires and Ultrafires cannot handle the current draw due to their protection circuit design and the Provari's boost circuit (which I only know a small amount about). Upon an overdraw, either the battery itself or the Provari may cut off with usage, as both are designed to do so as built-in safety features. If you vape at higher wattages then this will probably happen more frequently. From what I have read, the actual power of the Trustfire is closer to around 700-800mah-ish. With a heavy load like the Provari, the LiMn cells of the AW IMR should give a similar run time to the LiCo batteries in question. Additionally, the IMR will likely give an extended service life as the IMR is better made for the task that the battery will perform with the Provari. The physical dimensions of the Trustfire may also be slightly different than the AW IMR, the latter in which the Provari is specifically designed to use. Panasonic IMR cells also seem to be golden, but as of now it seems only 18650s are available.