Hi!
I have 4 chihuahuas and they are my favorite breed.
Three out of my four are VERY active. They can all go on long hikes and will go as far as I will take them. Tucker especially loves when we go to TN and can hike in the snow.
They're small... but are definitely far from delicate. In a lot of ways they remind me of terriers. They're very intelligent, definitely trainable, but not as biddable as Rory (my border collie). Rylie can break out of her crate within 5 minutes of being locked in it. They're good problem solvers.
All of mine are also big into jumping... and their favorite places are the tops of the couches. FAR from delicate dogs.
I wouldn't say they're one person dogs at all. They will equally love on both my husband and I. They are definitely lap dogs and want to be with you ALL THE TIME. They follow me into the bathroom. My lap is never free!
They also love to burrow under blankets- especially the short coated ones! Be careful where you sit
Mine all sleep under the covers in my bed at night as well.
They're generally a healthy breed, and very long lived. Average life expectancy is 12-20 years. Common health issues are luxating patella (find a breeder who health tests) and collapsing trachea (use a harness when walking them).
Rory is my barkiest dog... so chihuahuas aren't as "yappy" as their reputation says! Rylie likes to bark out the window. Haha. The others will only bark if there's a noise to alert them.
Breed standard calls for 2-6lbs. Most often you'll find them weighing 4-7lbs. There are only two types of chihuahuas- long coats and short coats. Like I said, they are STURDY dogs for being so small!
I had typed up more, but Chaz ate it... so if you have any questions just feel free to ask!