Castro Activ is 34.95 for 4 litres which is 8.70 per litre'
Penrite synthetic is 64.95 for 6 litres which is 10.80 per litre.
Thats not a huge difference. Either would be good choice and as my local dealer told me when buying coolant etc recently Castrol supplies the Honda oil at present. So the active may be the same as the Honda OEM oil.