No idea as to the prices, but i have had both parts, and also equipment [Tig footpedals] built to order from these people and they were all very good indeed. They are the most helpful people too..
From all accounts REALLY good... Check out the duty cycle. There are LOADS of sets that say "250A" or whatever, but then you find they can only be used for 1 minute and then need the other 9 to cool down. The duty cycle you see is the percentage of 10 minutes you can use the thing with the balance of the 10 minutes used for cooling. In general, in industry, 60% is used as the most a set can supply as the things will have very hard use. It is reckoned that you would do 6 mins welding then 4 mins wire brushing checking and general mesing about!!
Anyway, check the duty cycle on these things....
I have had a few items from these people and I have been delighted every time.