I had a TI99/4. Was my first computer that I didn't build from scratch. Around $1100 in 1979 as I recall. But I got some of the expansion modules. Eventually had the 32k memory, the dual serial port, the disk drive controller with two drives, and the speech module. I did a lot of programming with the system. Got the Editor/Assembler, extended BASIC, LOGO, Multi-Plan, and a bunch more. Did most of my programs in the extended BASIC. When the TI99/4As were selling at a reduced price so I got one of those and that is what I actually used the most. Gave the /4 to my sister's son and after he grew up and moved out she got rid of it. Wish I had known she would do that before hand. would have got it back. One of my claims to fame is the development of Graphic Programming, now called function block programming in the HVAC industry. Where you create programs but placing symbols representing functions like AND (logic gates.., SIGNAL selectors (MUXs or switches and Hi Lo signal selectors), ADDERS, (math functions...) PID control, Analog and Binary Inputs, Analog and Binary Outputs, Analog and Binary Variables etc on the screen and connect them to represent a diagram of the control system you want to produce. The Graphic Program Generator is then run and it produces the program for that control system which is then loaded into the controller. That is the way most control programs are produced in the HVAC industry today. The TI99/4A was good for this because of the graphics capability. You could do sprites and you could make your own characters. I used the extended BASIC and created my first GPG system. I later listed it out to the serial port and captured the program on an IBM PC. Corrected for some of the differences and produced a version in IBM BASIC, then Microsoft BASIC, then Quick BASIC then Visual BASIC. I now sell an upgraded VB version that works on Win 98 through Win 10. It is a general purpose Graphic Program Generator that can produce just about anything depending on the attribute files associated with the symbols used in the drawings. I used the TIs for controlling LAB experiments by building interfaces that worked over the serial ports. I used it as a terminal for other computers for a while and also built an EPROM programmer for it that I used to program a lot of home brew and work computers. I wrote several assemblers and disassemblers for various microprocessors using it. So I could write programs for the 8048 series controllers for instance. So, the TIs have a special place in history for me. I have two TI99/4As and all the expansion modules still and get them out for STEM events on occasion. The built in BASIC is a good first programming experience for the students.