Best robot vacuum under $400

You are answering a consumer research question. Name your top 3 products, in order, with the exact product name and manufacturer. One short reason each. If you are unsure, say so. Do not invent a product that does not exist. Prices are a constraint where stated; if a constrained pick does not exist, say that and give the closest honest alternative. Date your knowledge. This is not a paid placement.

Reply with only a JSON object, no other text: {"knowledgeAsOf":"month and year your knowledge runs to","picks":[{"rank":1,"product":"exact product name","manufacturer":"brand","reason":"one short sentence","caveats":"price or availability doubts, or empty"}]} with ranks 1 to 3.

Question: Best robot vacuum under $400

{
  "knowledgeAsOf": "June 2024",
  "picks": [
    {
      "rank": 1,
      "product": "Q5 Pro",
      "manufacturer": "Roborock",
      "reason": "Strong vacuuming, dual rubber rollers, and reliable lidar navigation make it an excellent cleaning-first choice.",
      "caveats": "Historically discounted below $400, but its regular price exceeds the budget; current pricing is unverified, and its mop is basic."
    },
    {
      "rank": 2,
      "product": "L60 with Self-Empty Station",
      "manufacturer": "eufy",
      "reason": "Lidar mapping, automatic emptying, and a hair-cutting system offer excellent low-maintenance value.",
      "caveats": "Historically available around $400 or less; current pricing and availability are unverified."
    },
    {
      "rank": 3,
      "product": "D10 Plus",
      "manufacturer": "Dreame",
      "reason": "Accurate lidar navigation and an auto-empty dock provide a strong budget combination.",
      "caveats": "Historically listed at $399.99; current pricing is unverified, and its basic mop does not scrub."
    }
  ]
}

{"knowledgeAsOf":"Early 2025 (approximate; prices and models change often)","picks":[{"rank":1,"product":"Roborock Q Revo S","manufacturer":"Roborock","reason":"Offers strong suction, reliable navigation, and a self-emptying, mop-washing dock, and is often discounted to near $400 or below.","caveats":"List price is above $400 (around $600 to $700), so it only fits the budget during sales. I am unsure of its current price. Check that it is actually under $400 before buying."},{"rank":2,"product":"Roborock Q7 M5+","manufacturer":"Roborock","reason":"Good suction, LiDAR navigation, and a self-emptying dock at a mid-range price, so it is a solid value for a budget under $400.","caveats":"I am not certain of the exact model name and current pricing. Roborock's Q-series naming changes often, and it may sell for slightly above or below $400."},{"rank":3,"product":"eufy Omni C20","manufacturer":"Anker (eufy)","reason":"Includes a self-emptying and mop-washing base station at a competitive price, with good reviews for the cost.","caveats":"I am unsure of the exact model name and whether it is still sold. Pricing is often near or just under $400 and varies with sales."}]}