The rapid diffusion of low-cost Simultaneous Localization and Mapping (SLAM), based mobile laser scanners is reshaping indoor surveying by enabling fast kinematic acquisitions with limited operational constraints, while raising critical questions regarding metric reliability and geometric fidelity. This paper presents a comparative assessment of four commercial SLAM-based scanners spanning different market segments, from entry-level to professional-grade solutions. The analysis focuses on point cloud quality, geometric noise, registration stability, and the preservation of planar surfaces and sharp edges under controlled indoor conditions. <br />For objective validation, SLAM-derived point clouds were compared with reference datasets acquired using a high-precision terrestrial laser scanner and a multi-station instrument certified to international metrological standards. All datasets were collected following a standardized experimental protocol and processed using proprietary software without additional filtering to isolate intrinsic system performance. Quantitative evaluation relied on target-based registration accuracy and planar section analysis, complemented by a qualitative assessment of noise patterns and edge preservation. The results reveal a clear stratification among systems. Mid-range devices demonstrate strong geometric performance, in some cases comparable to professional solutions, largely due to advanced processing algorithms, whereas the entry-level system exhibits significant limitations in noise control and geometric stability. The findings highlight a non-linear relationship between cost and performance and highlight the relevance of standardized validation protocols to support informed adoption of SLAM technologies in professional surveying workflows.