Minority parties get more seats.
Small parties don’t necessarily get a larger share of seats – some systems, like the “mixed member” system of Germany, put minimum limits on the share of the vote (as high as 5%), that exclude smaller parties.
- Parties will be weakened
PR can give more power to parties. A purely proportional system normally allows parties to control the selection of candidates completely, leading to politicians with much stronger party loyalty. Some systems work against this, especially ones with constituencies, but there’s almost always a party-selection element.
- There will be no independents
Independents can still stand, especially in systems that have constituencies that are then topped-up – they do especially well if they have a national profile though.
- You still have to choose one party
It doesn’t mean you just have to choose one party – a preferential system allows you to list parties/candidates in order of preference or leave them out completely.
- It’s too complicated for Britain
It does work with Britain – we already use it in the European elections, and Scotland and Wales. And it’s less complicated than guessing the intentions of your fellow constituents to vote tactically on the basis of poorly-biased voting-intention polls.