Well this is a) a very good and important question and b) a very difficult question
To be able to provide a quality recommendation we would first need to know what are you looking for and what do you want to cook and how do you want to cook and how do you like to cook
Most people buy the same thing as they did see at a friends home or by recommendations which is great but a detailed questionary and analysis is needed to provide the right recommendation.
Frist a so called BBQ is usually a Grill so direct grilling (with any heat source as charcoal or gas or electric or even wood) and this is not BBQ. Most people like to use the word BBQ because it sounds better and everybody is using this term
By definition BBQ is low temperature indirect wood long term cooking
A direct grill is fast and a gas grill is even faster as a charcoal grill and therefore if the fast readiness of the heat source is very important it is a clear go for gas
If somebody wants direct but a bit fire atmosphere a charcoal grill is good
if somebody wants to cook large pieces or wants to get a lot of taste and wants to cook carefully keeping all vitamines you must reduce the temperature and you must cook indirect and best with wood as only there you add flavour (this is why charcoal and or gas grills recommend wood chips to be added to get more taste to the charcoal grilling)
A Smoker is not only a Smoker you can Grill and BBQ and Smoke so a 3 in 1 unit
If somebody likes or even loves outdoor cooking you need ideally several grills and several heat sources and you can select like this depending what you want to cook and how you want to cook and what result you want to achieve you select the BBQ
Myself i usually have 4 per house (there is a certain limit by my most loved wife not more than 4 units per house – luckily i have 2 homes a vacation place and a main place – like this i got 8 BBQ’s)
I have obviously at each house a smoker and a gas or an outdoor gas cooking station, an outdoor electric BBQ with Ceramic fields, wood pizza oven (small) and for fast cooking 1 kg in 10 min a Beefer what else
If i want to cook 1 kg of Beef Filet i usually use the Gas grill for convenience and low temperature cooking does not really add much to the filet as the meat is already the top quality you can not really improve the qualilty much there is only the ‘danger’ to destroy the quality with the wrong cooking method. In aprox. 30 minutes the Filet is ready of course rare or maximum medium rare for the respect of the animal please)
A Salmon i can only BBQ with wood in a smoker the so called semi cuit BBQ Salmon (the Swiss Hotel school did many years told me this is the professional name for what i was doing with the salmon). Skin on the half of the salmon and skin down and in 50 min prior the protein (the white pearls start to pop out of the salmon) take it and serve it – there is no better way of salmon out door cooking if you like it humid and not dry and still a bit rare inside and flavour and color outside
A Prime Rib large piece never under 3 kg best 6 kg or more can only be gently cooked on a BBQ Smoker
A Ceramic BBQ cooking stly which recently entered Europe (this is by the way a very old Asian and Eastern outdoor cooking method) can cook almost everything.
You need to learn and spend some time and best a cooking class till you really discover and know everything how to use the unit perfectly but also a great way to cook