Here is a very rough comparison of the costs of mains and 18V power tools. The comparisons are between Einhell, Makita, deWalt, Milwaukee and Bosch. The comparisons are rough and ready, using the cheapest available items in each category in Screwfix, Toolstation and Wickes online as sources for the prices. There was no attempt to match specifications, for instance by ensuring that all were brushless, etc. Milwaukee corded tools are not included because they do not seem to be generally.
Don’t compare directly the Total, excluding battery, column for corded and cordless, because the former does not have an impact driver included.
The brands are in price order with Einhell by far the cheapest and Bosch most expensive.
Thoughts:
1. There is not an awful lot of difference between the main brands, particularly since I noticed that the Bosch cordless tools are particularly highly specified, which accounts for some of the price premium over the others. A friend whose judgement I trust says that the Milwaukee quality is better than Makita.
2. The cordless premium is calculated by subtracting the corded prices in the corded column from those in the cordless. As can be seen, the cordless premium is relatively low (around 10% when one takes into account the previously mentioned high specifications of Bosch cordless). So, once one has the batteries and charger, one might as well go cordless.
3. All brands have one or two cheap offers which bundle a couple of batteries and a charger, making the transition to cordless less than the prices above indicate.
4. Makita LXT was launched in 2005 and is still their major brand. So the technology is mature and obsolescence of currently purchased tools unlikely to be a problem.
5. Makita is a market leader and it may be that its ubiquity stimulates competition which tends to drive the price down.
Relevant reviews
https://www.pyracantha.co.uk/top-6-best-impact-driver-reviews/
On Trustpilot, Einhell seems to get poor reviews, whereas Einhell UK gets good ones. Bizarre. Toolstation has variable reviews of Einhell. Wickes has generally good reviews of the brand.
https://uk.trustpilot.com/review/einhell.co.uk
https://uk.trustpilot.com/review/www.einhell.com
Makita seems to have chuck problems. See for instance:
https://www.screwfix.com/p/makita-m8101k-710w-electric-percussion-drill-240v/3043r
Other random thoughts
Mainstream manufacturers are also producing 10.8 V or 12 V tools in addition to 18 V. I suppose that ‘small and light’ must be the aim. At the same time there is a tendency to move to higher voltages for beefier tools, sometimes double 18 V and sometimes treble. So the battery market seems to be getting more diverse rather than more standardised.