I am having wonderful success with these sock style bird feeders. They were purchased as a supplement/spare to my existing feeders. I had one existing white color feeder of a different brand which became over populated resulting in squabbling and competition. I added a second feeder which resolved the crowding issue. Then decided to purchase this brand feeder as an extra and replacement source. These feeders are about 1/3 larger than the existing feeders, they are sturdy, with a closing clip, and will hold well over a pound of thistle seed. There are two colors, black and white. The black work as effectively as the white, and attract the birds immediately without issue. The holes are somewhat larger than my old feeders, but do not seem to be an issue. Yes as with all sock feeders there is an issue with spillage when filling the feeder with thistle seed. The folding funnels supplied with the socks work great.To avoid a mess in the house, I fill the sock outside on a patio table and then sweep the fallen seed onto the grass under the feeders. The seed on the ground attracks Mourning Doves, I have had as many as 8 Mourning Doves foraging for the thistle seed, under the feeders at one time. All the feeders attract birds equally, I mainly have Lesser Goldfinch, both green backed and black backed, House Finch and Pine Siskins. This time of year with juveniles, females and males all at the same time my skills in species identity are little rusty. On the 3 feeders at one time there have been as many as 20 birds total. I do have a small water feature near the feeders a fountain where the birds also congregate. These thistle feeder socks are fantastic, I fully recomment them. They fill and hang easily, and do their intended job effectively.