Choosing the right model depends on your priorities, your gear and your budget.
Factors to consider: harness compatibility (does it fit into the reserve pouch and can I get it out again?), certification (must be EN 12491), opening time (mostly about 3-4 seconds), descent rate (at max load, your all-up flying weight), stability (pendulum resistance, and down-planing), steering, ease of use, build quality, price, system weight, packing (complexity, cost, availability of packers) and age. Make sure you are comparing the same kinds of reserves when comparing sizes (e.g. a PDA round reserve to another PDA round reserve).
Want expert help choosing the right and best gear for YOU? First we find out your all-up weight and purchasing priorities, and explain the pros and cons of each type of reserve. Then we sort and filter the options by maximum load to narrow down the choices. We continue to filter down the choices based on your buying priorities. From years of experience this works really well, and the results can be surprising.
In practice we have found that, whilst certain reserve models tend to mostly come out tops, this changes with time (new reserves appear, prices change) and it also varies quite a bit based on the pilot’s all-up weight and their buying priorities.