It depends on what you are trying to support, underlying soil conditions, site access, noise limits, etc.
For example; if you are doing a foundation retrofit or adding additional supports in the interior of a building, there might be limited access or headroom clearance. Here, minipiles can be a good choice installed with fairly small hydraulic, compressed-air or propane powered auger rigs.
Alternatively, you might consider augered helical piles or resistance piers in the above situations. We use these in place of conventional grouted minipiles in our practice as these can be installed as fast or faster with a smaller crew at the same or lower cost than the minipiles. Atlas Systems makes an excellent product for these applications.
If noise and vibration limits are critical at the site, minipiles can be a good choice in place of driven steel or timber piles for new construction. Design capacities tend to be in the 20 to 60 ton range for the typical 6 to 8-in diameter augered minipile. The piles can be designed for end bearing, friction, or a combination of support.