As a Bulgarian I agree with MichaelA380, fortunately usually IC Sofia does not disappoint thanks to the great staff and management.

I think transportation is always an interesting topic, different people value different things. Some people want to delegate it to the hotel (which usually is more expensive), other are interested in cost or convenience.
Guilty as charged using once IC Berlin transfer for 2 people costing only... 190EUR

Speaking about Sofia my humble opinion is (one way):

Hotel transfer - As stated above 65EUR, in the past they were using Audi A6
Other transfer services (Meet and Greet) - Sometimes I am using a specific company, if interested please DM me for a link (I am not affiliated, nor earning any commission). Price To/From Airport To/From any point in Sofia is 30EUR (1-3 passengers) 50EUR (4-8 passengers). They also have other options. I am using them for years for transfers in Bulgaria and they never disappoint
Taxi - 9-12EUR (approx price by the official taxi company - Yellow). Here for me the big Q is can they take all your luggage as sometimes trunks are kinda small (shall not be an issue at the airport). Usually they accept card payments. If you want to use them in the city they have a convenient application where a card can be added and you can pay directly through the application.
Metro - The cheapest option which is very convenient if you don't have bulky/heavy luggage - 0.60EUR and stop very close to the hotel. Here the interesting detail is that by the rules you are allowed 2 pieces of hand luggage, for every additional one you need another ticket. It is even more interesting what is considered as hand luggage. As per the law it is: 10. "Hand luggage" means any type of item carried under the direct control of the passenger by the use of the passenger's own physical strength. (https://sofia-obshtini-bg.translate....x_tr_hist=true Chapter VIII). Does it sound funny, strange etc - Yes. Is it enforced - I have no idea, usually I am taking the taxi. Here the big pro - nothing can beat the metro timewise during rush hour.
Bus - Same rules like the metro with some cons - it is slower, it stops further away that the metro and rush hour can be a killer. Last resort option if Metro is not running

f0zzyNUE Let me know if I can help with some info about Sofia