The Lenovo S21e has an Intel Celeron processor family which is better than most many processor core laptops that have been around for around the same time as it. Most many processor core laptops that were launched around the same time as it have an Intel Core i7 processor family.
This notebook PC's processor family (Intel Celeron) is in fact the worst processor family amongst all many processor core laptops that were released more than a year ago.
Amongst similar types of notebook PC the best processor family is Intel Core i7-4xxx.
If the processor family of this notebook PC is too bad for you then you might also want to consider the Toshiba Satellite C55-B (£629.55) (Intel Pentium).