The price of the mole is $12.95 in the US. Import one to the UK you need to add 20% VAT which makes a total of $15.54 - about £11. Plus you have to assemble it yourself, I believe, and there are no internal switches for frog polarity etc. Tortoises can be bought for around £12.50 in the UK if purchased in packs of 6 or 12.
Both Alan and I are running automation with RR&Co. In this environment reliability is paramount, as the software is changing turnouts and won't know if one failed. I'm quite happy to spend a little more to get the most reliable point motor, which is why I went for Tortoises. More than 70 in use for nearly 4 years and not a single failure.