Quite a lot of people dislike Tag Heuer and I can understand why. Their entry-level models still have ETA or Sellita movements and at the same time, Tag Heuer's watches cost more than watches on a similar quality level - such as Longines Hydroconquest and Oris Aquis.
Producing in-house automatic movement is extremely expensive and this is the reason why many microbrands outsource the movements from established movement manufacturers such as Sellita. Here is a thing though - the mass-produces ETA and Sellita movements' quality is very good. The quality is often better and more reliable than many in-house movements produced by brands.
Tag Heuer's best-selling watches are the Aquaracers and Carrera (non-chronograph) and many of them have Tag Heuer's Calibre 5 movement or its variants (e.g. Calibre 6, etc.), which are all based on ETA and Sellita movements.
Tag Heuer is more than capable of producing in-house movements as they already offer them. If they were to put in-house movements into the Aquaracers as an example, the price of the Aquaracer would rise significantly. With this new price tag, Tag Heuer will compete against the likes of Omega, which is, at this stage, impossible to beat. Omega's Seamaster is iconic, proven and arguably even better than the Rolex Submariner.
I have owned Tag Heuer Aquaracer Calibre 5 and currently have the GMT "Pepsi", which is pictured above. One thing I can say about Tag Heuer is that apart from the movement of the entry-level models, every other aspect exceeds when compared to not only similar-level brands but also brands above. Let me explain.
When I think of all the luxury watch brands below the high-end level (i.e. Patek Philippe, Breguet, Blancpain, etc.), Tag Heuer makes one of the most sturdy cases and bracelets out there, even better than Omega. The only brand that makes better quality than Tag Heuer in a similar tier range is Rolex. On top of that, Tag Heuer's design is unique, eye-catching and balanced.
I have also met many people who dislike Tag Heuer but every single one of them never actually owned a Tag Heuer watch before. Yes, the movement is a very important part of the watch but when you are paying under $4,000 USD for a watch, you should not be expecting the watch to have everything. To me, Tag Heuer's brand power, design, quality and history back up the price point they offer - there are many people who like the old Heuer watches better but for me personally, they look outdated.
If you are looking to buy a luxury watch with a modern design and high quality, I strongly recommend any of the Tag Heuer Aquaracers with automatic movement. The design is different to most of the diver watches out there and with many colours/models to choose from, the Aquaracer is a watch you can wear daily.
However, if I had to pick one thing I am not a fan of Tag Heuer... That is the power reserve is quite short. In the current standard, I personally think an automatic watch should have at least 50 hours of power reserve.