SAA Watercolours

I've recently joined the SAA, and placed an order for some materials with them - as part of this I decided to order a tube of their Burnt Sienna to try it. I haven't done a great deal of painting at all, but have mainly used W&N and a few Daler Rowney Artist's colours so far. I was pretty impressed by the SAA paint, and at £4.70 for 14ml, as opposed to over £8 for the W&N equivalent, it appeared good value indeed. It wasn't quite the same as the W&N - it seemed thicker out of the tube, but once diluted it performed fine & I couldn't tell any difference in the end result after dashing of some comparative graduated washes. What I'd like to know from someone more experienced than me (virtually anyone then!), is whether a). I'm wrong, & W&N or similar are a lot better, or maybe b). It's because I chose an earth colour. I'm astonished that SAA are also selling Cadmium Red at £4.70 for 14ml (& their website says it is genuinely Cadmium), as opposed to around £14 for W&N. Surely this must be of inferior quality?? Of course, I'm only asking advice because I'm too mean to try it!