Hi John
Appreciating Koi is about just that, looking at the positives in fish rather than the negatives.
The perfect Koi doesn’t exist, whether you pay £50, or more than £10k

for a Nisai. - and believe me it‘s a lot easier to trash an expensive Koi than a cheap one

.
With a new pond pond and filters the first few fish going in there are going to have a toughish time short term whilst everything matures - bear this in mind when considering the initial purchases.
As Koi get older, they will both grow and they will develop "beauty" wise, they will reach peaks in both size and beauty, how high these peaks are, whether they will last and whether they coincide is the challenge when selecting a fish.
It's not easy answering questions on whether a Koi is "good" or not, straight away you need to start making judgements against other fish and price comes into the equation. Suffice to say these fish all look sensible purchases provided you are happy that the price was reasonable.
Dave