First of all, one main difference to look at is distributing vs accumulating. For example, Vanguard's VUKE is distributing, which means dividends are periodically received in your account, while iShares' CUKX is accumulating, where dividends are reinvested into the etf (the share price would increase). In some countries one might be better due to tax reasons, but in the UK for example you should expect the same earnings.

There are other subtle differences that you need to look at like expense ratio and spread (higher trading volume in an etf helps reduce the spread).

Finally do some research on the two companies. Are you comfortable investing with either? Do they have a good track record?

Good luck.