I don't know what you are really totally looking for in these so I'll throw my .02 up here with a wall of text per usual....
I've owned 3 Tandy 1000's, an SX, an EX, and the 1000A I'm still currently using.
The 1000 SX and EX are basically the same machine except the EX is all-in-one. Both are 6MHz 8088's that can run at 4.77MHz if one of the first four function keys are pressed at startup. The SX often comes with dual floppies. Both top out at 640K RAM.
The EX has 3 plus slots, which are ISA compatible but you need some kind of adapter to use regular desktop boards in them (I've seen independant builders making cards for these). Most common config I see these come with is some kind of very old internal modem and a 640K upgrade card. They only allow for one Floppy Drive (1x 360K DSDD 5.25", usually TEAC branded). The power cable is hard wired, and the keyboard is basically the same as the regular 85 key Tandy keyboard. One nice thing about the EX is the volume knob is outside the case.
The SX has 5 ISA Expansion slots. Memory can be upgraded to 640K from 384K base model RAM using eight 40256 SDRAM chips (details fuzzy, I'd double check). Most should already be 640K though. The 1000 SX has the volume control for the speaker inside the case so kind of a pain if you find it too quiet or too loud. Usually the SX came with 2 360K DSDD TEAC Floppy drives with white faces.
I'll throw the 1000A out there for ya as well since that's what I currently have. The 1000A is the revised version of the first release. It's much the same as the SX except you only have 3 ISA slots, a much smaller case, RAM upgrade from 640K comes in the form of an expansion card leaving two slots. These had 2 360K TEAC Floppies with black faces and a black power switch on the right rear. I'm quite digging mine despite it being a 4.77MHz machine. Funning Sierra AGI games in "Fast" will produce comfortable gameplay speed in things like Kings Quest and Leisure Suit Larry. Thdexter and Silkworm also run great on it. Mine has a 640K upgrade in it, with the other two ISA cards being a Realtek RTL8019 network card for using mTCP/FTPSRV on it so I can move files to it over the network and get on the Internet (the Tandy 1000 series is GREAT for BBS surfing over Telnet), and an XT-IDE card with a 3GB Seagate HDD on it.
The Tandy 1000 series have TRS-80 gameport jacks on the front which worth with both analog joysticks, and the Tandy Color Mouse and Deluxe Mouse. I actually have the latter. Just a word of note - if you manage to find one of these mice, they don't work like normal mice. They need drivers from as they actually behave like a one or two button joystick respectively, with the ball being replacement for the stick - so the movement ends after a certain point - you'll feel it and hear it a little as the ball sticks against the roller that refuses to move any further.
General Graphics stuff - The Tandy 1000 machines I've owned all had a "TV Mode" used by composite by holding F12 while starting up - though I think the EX/SX had it on "F4" instead. If you load the Tandy without pressing this, the Composite port goes to high resolution monochrome mode and looks really crisp but you won't have any color. "TV Mode" puts it into 40 column Composite mode with the whole "fringing/holoflash" thing going on with the text that gets you extra colors in CGA Composite mode - so that's a real benefit for games, but a bit stinky if you want to run it like a COnsole and have to do things through DOS on a TV set. On the 4.77 MHz models and even the 6MHz models you will feel it lag a little in 320x200 16 mode speed-wise because that's about as much as this machine can handle - it is, after all, an XT-Class PC with an 8088.
Sound-wise. It uses the Texas Instruments SN76489 sound chip which produces 3 channels of square wave audio, using the actual PIT-based internal speaker (regular PC speaker) for a fourth channel in some software. Sound is somewhere in the ballpark of an 8-bit NES or an MSX computer from Japan. Honestly, I wish I knew how to program - I'd be porting the old NES Dragon Quest games to it!
Maybe I'll post pictures later of the glory of the Tandy's video modes since my 1000A is running into my TV and an NEC MultiSync II color monitor at the same time right now in my closet.
