Pro's and con's of citizenship

Depends what nationality you are.
If you are British and worried about Brexit, the big advantage is that you will still be able to live, travel and work in any EU country.

As a Belgian, you are taxed on your worldwide income if you're also a Belgian resident.
You also HAVE to vote.

Pros: You are a Belgian and EU citizen; you may be able to renounce your original nationality; you can vote in all elections.

In my Embassy/Consulate there is a minimum of 4 months waiting list to renew a passport or ID Card. Now I can simply go to the Commune next door have the Belgian passport or ID card renewed in less than a week (and is cheaper too!).

Lloyds decided to move to Brussels because they are sure there will never be a Brexit equivalent in this country. I guess it works for me too considering the politics back home.

Very shortly: pro you are official citizen of Belgium
Con- you have to vote.

For the rest it really depends on your specific situation, for example for me the biggest pro was that i don't need to travel to Brussels to embassy every time i had to do administrative matters linked to my nationality. Silly but true ;)

As I think you're British

PRO. You get a dinky credit card sized passport and the ability to travel (with full rights to healthcare), settle and work anywhere in the EU, as well as Switzerland and Norway. You get to vote in the local, national and EU elections in Belgium. You will be able to use the "EU" lane in the airport when you go on holiday. And you don't have to fork out a fortune for a nostalgic blue UK passport.

CON. None.

@CM
You get a dinky credit card sized ID CARD which acts as a passport in the EU and various other close-by countries if you are travelling as a tourist but you still need a real passport to go to, say, US, Australia, S Africa etc, etc. And such a passport is more expensive than a UK one..
And - your Belgian ID is valid for 40 years on first renewal after you reach retirement age.

If you do need to travel outside Europe, you can order the required passport through your commune (and its costs LESS than a UK one) - while the passport photos can be done just about anywhere. (Because UK uses a non-standard colour background you can easily find that there isn't a photographer with 100 km who can do your passport photographs for you.)

....... and you won't need to register for ESTIA in 2021.

@Kasseistamper. In fact Belgian passports are about 30 euros cheaper than getting a renewed UK passport if you live in Belgium.

I stupidly quoted the info which my son had given me. I've now read Wiki.
Both UK and Belgian passports are available in 2 sizes.
My son - who travels extensively - has the 64 page Belgian version which costs €240.00; almost 4 times the cost of a 32 page version.
The UK 'big' one costs only an extra tenner.