ive used the, here and there, had some good ones, hell i have a 3 year old 550W that worked pretty good until i outgrew it, but then i got a 600W version that was noisy as all get out, i dont trust the higher end ones to be totally honest, and they can be rebrandings of the major manufacturers, just have to know what model you are looking at...rosewill is neweggs in house brand, their product is often a rebranding of someone elses product
My mum, sister and step dad all have pre built systems, my mum's I took apart a couple months back to clean, and it has a 230W cheap ass PSU in there. It powers it and is adequate, that doesn't make it good.
What you said about rebranding is true, but why does that make them bad? The vast majority of the better units are made by other companies such as seasonic or CWT, both are great manufacturers of power supplies, which is why your Antec, Corsair, XFX etc are so good. they do make some cheaper, bad units, but the decent brands don't tend to get them, with the exception of some of the Antec, Thermaltake, Be Quiet! etc lines.
You can say Rosewill are good units, but it is just words. Look at actual figures, you will find lower efficiency (therefore more heat and sound produced), faster degredation, less stable power and either lack of, or not very good OVP, UVP etc