I'd go with the Arab. They both sound sweet, but size wise for trails and such the Arab would be just easier I think. As horselvr said, TB's I think are a little more upkeep. My Arab mare Dandy (avatar) is 24 years old!!! *the picture was taken 2 years ago, but there is no difference. Her feet are AMAZING, hardly ever need trimming. Just in the winter here and there. In the summer, they pretty much stay worn down nicely. Super tough, never ouchy. She's strong, is a reasonably easy keeper (no supplements or anything, just hay and grazing). Perfect size for getting on and off. I'd put anyone on her. She's super smart and loving. When people come over and I'm like "She's 24" people are like
What?!?!?! No way!!!! She has LOTS of controllable
spunk. I've put very young, never sat on a horse in their life, kids on her and gone for a trail ride and she just babysits them.
Not saying all Arabs are like this, and not saying that TB wouldn't be that either. Above is just my experience with my Arab. I've known 4 other Arabs (besides Dandy) and worked closely with 3 Arabs. One mare, I'm sorry, was quite the airhead!!! Really frustrating to work with. The gelding was SUPER calm, like he didn't care about much really. <--could put anyone on him. The 3rd mare was pretty cool, not as stable minded as Dandy. She had a more quiet personality and was very sensitive to cues. People had to know what they were doing on her, green riders would just confuse and upset her.
They come in all personalities. It's really up to you though and the individual horse. You'll see which one you feel more connected with. I'd really suggest asking for a trial period though first. Just to make sure once you get them home they are a good fit for you and your environment. Try and fit in things you'd be doing with them. See how they do being saddled, brushed, feet messed with ect..
---The said above crazy airhead Arab mare was bought under the pretense of ANYONE can ride. Perfect trail horse. Kids horse. She was exactly the opposite of ALL those things! In my opinion she was green and not stable minded enough for a beginner rider. She needed A LOT of work.
Good luck! Let us know who you pick!!!