Market value, assets, and number of corps are all cute. But in business, the most important thing is money. 'Madoff'
Speaking from my own experience on here the only time I start to sell my corps is if I need to raise some money fast. By usuallly by 'IPO ing' them (selling shares) which have very high market values. To put it in simple terms for relatively new players, the market value of a corp is also how much you can get for them in shares as well, which is a long process, not just to sell the whole corp as one.
So if you want to run your enterprise like an equity company, selling shares is definitely the way forward and can be extremely profitable when sold at the right time, usually when they're in high demand.
Or be like a dealer where you create and sell corps as one where you will get the total market value of it in a lump sum. Although the high value corps will be hard to sell since it is much cheaper to build them yourself.