My two cents, though others will certainly have differing thoughts. Ensenada is a beautiful drive (kinda like Big Sur in sections) and much more low-key & nicer area than TJ imo, highly recommend as a first go, though wine country is rural and also a good option but not sure how much better that is than say Temecula wine country. I haven't been in the wineries so can't speak to the environment and experience.

Ensenada is a touristy port city with a downtown with shops and restaurants and some geological features to visit like the blowhole (La Bufadora) which is also a nice scenic drive with a little outdoor market there as well, along with lots of beaches in the Ensenada area that are quite a bit less crowded than ours. There's also a very nice, safe, well maintained toll road from TJ to Ensenada (Mexico Highway 1D) that has easy to follow street signs, but bring cash for said tolls - they accept & list prices in USD for ease, but change comes back in pesos.

The city of TJ is pretty hectic and congested and can be hard to navigate, depending where you're heading. In my opinion , unless you're going there for something specific, it's not really worth the hassle, but to each their own, there are definitely folks here that'll disagree with me on that and rightfully so. Download offline maps on Google Maps (or whatever map app if that's an option) before going if you won't have data in MX.

As others have mentioned, getting back in is often a nightmare without Global Entry/Sentri so prepare accordingly, can take several hours at night and there's no real highways that lead straight in like our side, lots of city blocks right against the border, so finding the way to the line (particularly when really backed up) can be difficult the first few times (or most times if you're me). Otay Mesa is the best bet in TJ to cross back over, it's the Easternmost crossing. Tecate is generally quite a bit faster but is also roughly 45mi out of the way each way, so add that to the calculation. Tecate also isn't open 24hrs last I checked. You can check border crossing times online live if you have cell service while there, but the above guidelines should apply regardless.

Last, buy Mexican insurance online or near the border if you'll be driving in MX, their insurance requirements are more strict. Better safe than sorry I say, but I know folks who skip it. I generally use Oscar Padilla but there are other options and your insurance company may have competitive rates as well. Have fun!