All international TLD extensions are the same if it comes down to ranking purposes so it doesn’t really matter which domain extension you will choose.
You should know that the domain extension does not really matter if the visits to your website are through links.
If you want to use it for branding though, your choice depends on how you want to brand your company, because a specific domains are used for specific purposes. For example, if you want to target only a market in UK it is very advisable for you to use a .uk extension for your business rather than .com.
Also, it is your decision to choose whether or not you want to build your business idea on a domain where the .com variant is taken by someone else. You will never be able to predict and control what will happen with this domain in the long run. Maybe you are facing the risk of loosing traffic and if later you decide to resale the domain your chance of this will be lower.
If you decide you still want a .com domain extention for your website after all the reseach that you’ve done – here’s what you should do:
Ask yourself what type of visitors will come to your website, what kind of a website your want to build? What is your audience of people? Is it international? Is it native? If it is a native audience you want, then just choose an extension from your own country. If your audience is international then it will be much difficult doing SEO, you will have competition with very well optimized, very popular and famous websites.
In order to build traffic to your website your goal must be for people to remember your website’s domain name and to be easy for them to find it just by typing it in their browser, your domain name must be very catchy.
Once you have achieved that you will have very well-laid strategy about the traffic to your website you can start thinking about the content – it must be high quality, it must be something very interesting so that people will start recommending you and go back to your website.
You don’t just build a website – you build a brand and this is what will make you successful.