I think it is down to experience and age.
If you are young and start in GA/Bizjets, chances are that you will get the need and the opportunity to get in the airlines and fly the bigger stuffs.
If on the other hand, you have joined the airlines without doing the Biz thingy, you might feel you have missed out on true flying and will be at least curious about this part of the industry or even go for it.
Then rather than comparing the aircraft size (and assuming you have a little bit of experience in the industry), you will think that what is most important is not the size but your lifestyle.
If you have what you want in the airlines, why change that (apart for my first point). If you are happy flying Bizjets then the same applies.
It is my personal opinion and experience that the airlines have changed a great deal in the past few years (locked door, dum security, 4/5 sector day, low cost model etc...). I was lucky enough to join what could be considered a "legacy airline" although a charter one. I was also lucky to see the transformation (not so successful so far) into a low cost model (or mixed model as per their words).
So I was lucky to see my future at an early stage and weighing the pros and cons, I decided to take a massive paycut (35-40%) to become a Bizjet pilot (NJE).
I have not been there very long but I have no regret and look at airline jobs coming through without the slightest will to go back to the routine.
I am happy were I live, I fly a nice aeroplane (XL), with nice crews to very varied destinations. I like night stops (and get plenty) but like being home a few days in a row too. I get all that.
I would like to see some things change within NJE but I also believe (naively some will say) that they are occuring.
So for me, I have done both and I know where I fit better. We are all different and so are our expectations, experiences.
Unless you have experience both, your gut feeling might be the best you have to decide where to go (and who offers you a job first).