Clear day is a very good option for the price, but it does have the downsides of silver with lower purity... exaggerated leading edges, adds a bit of harshness and less accurate vs upocc conductors, this can lead to long term listening fatigue. Performance for the price is good and may be the best option at that price point for some systems though. Initially they sound exciting, but over time you may notice some downsides.
GT, It's definitely a type of brass and it is probably their own alloy... They used to state they use brass and phosphor bronze for some things but it seems like they recently switched to "copper alloy", which I suppose they think sounds better. Regardless, Furutech connectors can be trusted to sound good. I do not use the FP-200Bs anymore as they are not as good as the much more expensive pure copper locking bananas, but they are not a bad sounding connector.