Comfort, practicality, weight: the choice between a 1 or 2-person tent depends on your personal characteristics and conditions of use.
Still unsure? Budget may also matter considerably. With comparable tents, choosing the 1-person model saves money. For a similar budget, you could afford a more technical 1-person tent than an ordinary 2-person model. However, this saving may prove questionable if, in 3 or 4 years, you discover you prefer wild camping as 2…
If in doubt, the 2-person tent remains the most versatile option.