Many years ago I tried Taxis Fiesta (as not to be confused with Fiesta Taxi in LA, Ca), and back then they were very fast, so I continued to call them instead of Yellow Cab, which seem to take forever south of 610. But a few months ago, Fiesta sent someone that couldn't even understand driving/directional English - serious, he didn't understand turn right at the 2nd light, so I had to sit so he could see me in his rear-view mirror when I pointed which direction turn, and at each intersection had to point forward rather than my silence being assumed as continue in same direction until I say otherwise.
Fiesta was in my phone's history, so I called Fiesta instead of Yellow Cab. I'm sitting in a lawn chair in the front yard, recalled Fiesta - 20 minutes after original call - to see how much longer before my taxi arrived. Dispatch told me they haven't even arranged for a taxi yet! Twenty minutes after my first call! I could understand if they said it was arranged, but still 5-10 miles away, but it wasn't even arranged yet after 20 minutes.
I'm going back with Yellow Cab - I setup an account on their website, and next time I need a taxi for a timed appointment, I'll setup with Yellow Cab the night before, with a 45 minute window. But I'm taking the truck on Monday to be 100% sure I make my rescheduled dr appt.