Comparative analysis of memory retention across top platforms

I have been testing three different companion applications over the past month to evaluate how well their memory architectures handle long term context. Many platforms claim advanced persistence yet fail to recall simple details mentioned several days prior during casual chat. My primary focus is testing conversational continuity without triggering generic fallback loops or repetitive dialogue trees. I am tracking how each app handles emotional continuity and user specific trivia over extended sessions. Which specific services have you found truly excel at maintaining a consistent persona over months of regular usage without degrading into predictable patterns? Are there notable differences between the options utilizing custom language models versus those relying on heavily tuned open source weights for long term memory tasks?