Choosing between a new Skywatcher 150 floor-standing Dobsonian and a used Skywatcher Virtuoso 150P comes down to your priorities and budget.
The Skywatcher 150 floor-standing Dobsonian is known for its simplicity, ease of use, and large aperture, providing excellent value for amateurs seeking good deep-sky performance. As a manual telescope, it requires manual tracking of objects, which can be educational for beginners eager to learn the night sky but might require patience.
On the other hand, a pre-owned Skywatcher Virtuoso 150P priced at $388 offers computerized tracking and potentially more features, like compact design and plug-and-play operation. The Virtuoso model might be attractive for those looking for convenience features, especially in urban settings with light pollution, where swapping viewing objects quickly is advantageous.
Considerations should include the condition and warranty of the used Virtuoso telescope, the difference in ease of use, and whether automated tracking (Virtuoso) or manual control (Dobsonian) better suits your observing style. If portability and ease of setup with automation are high on your checklist, the Virtuoso might be worth considering. In contrast, if maximum aperture and learning experience are priorities, the Dobsonian could be a better choice.