The idea with this tool is to push down on the soil, twisting right and left, thus boring a hole into the ground of the required depth, then you pull out a plug of earth. Next drop the bulb in the hole and put the plug back in. Presto, you’re done! It certainly sounds easy enough.
In actual fact, though, it rarely releases the plug on its own. You need to push it free or bang the tool on the ground, with the result that the plug falls apart and you usually end up using your hands to fill in the hole. Even spring-loaded models, supposedly designed specifically to release the plug easily, rarely do so without some extra effort.
And that’s not the only problem. The resulting hole is only wide enough for one medium size bulb, say a tulip, a hyacinth or a daffodil. It’s too wide for crocuses, squills, snowdrops, etc. and too narrow for crown imperials (Fritillaria imperialis). I’ve yet to see a bulb planter with an adjustable diameter.
Plus bulbous plants are generally too small to make much of an effect if planted alone: they need to be planted in groups. Try planting 20 tulip bulbs with a bulb planter and you’ll see: it requires a lot of effort.
Also, the current recommendation for tulip bulbs is to plant them extra deep, 12 inches (30 cm) down. This not only puts them out of the reach of squirrels, it helps perennialize them. Yet the average bulb planter is only about 6 inches (15 cm) high. So you’d have to drill a second hole on the bottom of the first one it get it right.
In my experience, it is far easier to use a simple garden shovel, which you already own, I’m sure, to dig a larger hole in which to place several to many bulbs at once. With a shovel, you can easily adjust the depth as required. For any precision planting, like when you’re planting bulbs in between established plants, a garden trowel does an equally good job and requires less effort than a bulb planter. And you probably already own one as well.
So, at least in my experience, this is one tool the average gardener really can live without!