It seems to be getting harder to find the R4DS - Revolution for DS these days. So we found the DSTT! The DSTT does everything the R4DS does, plus some. One of the main differences is the DSTT supports SDHC microSD cards. The DSTT also seems a bit cheaper as it comes bundle with your choice of microSD. Here are some good deals on the DSTT:

	DSTT for Nintendo DS	DSTTi for Nintendo DSi
Works with Nintendo DS?	Yes	Yes
Works with Nintendo DSi?	No	Yes
Support SDHC micro sd cards (4GB, 8GB,16GB,32GB)?	Yes - microSD: 4GB, 8GB, 16GB, 32GB	Yes - microSD: 4GB, 8GB, 16GB, 32GB
Firmware Software Included?	No (download below)	No (download below)
Current Firmware Version	DSTT v1.17 English Firmware (Official) DSTT v1.17a12 English Firmware (Unofficial)	DSTT v1.17 English Firmware (Official) DSTT v1.17a12 English Firmware (Unofficial)
Micro SD Card Reader included with package?	Included	Included
Does everything your friend told you it would do?	Yes	Yes
Compatible with DSi v1.4 firmware?	No	Yes
Where can I buy one?	iShopVideoGames	iShopVideoGames
Are they running any sales?	DSTT with 2GB microSDHC for $19.99 (FREE Shipping!)	DSTTi with 4GB microSDHC for $29.99 (FREE Shipping!)

Here's a comparison chart of the differences between the DSTT and the R4DS

Features	DSTT / DSTT	R4DS
DS original cartridge size, Slot1 interface.	YES	YES
Plug 'n Play, easy to use, just Drag 'n Drop file from PC to flash memory card.	YES	YES
No FlashMe, built-in NoPass, and the GBA cards in slot2 can be started directly.	YES	YES
Supports CleanROM, No covert.	YES	YES
100% SDHC TF and standard TF compatibility up to 4TB(4096GB) flash memory card.	YES	NO (onlySD)
High speed SDHC. Supports any TF card speed with no lag in game	YES	NO (only SD)
Save directly to TF card, not to onboard chip, Never lose your saves.	YES	YES
Automatically detect and generate save type.	YES	YES
Supports Moonshell and homebrew. DLDI auto-patching.	YES	YES
Supports FAT/FAT32, works on any OS.	YES	YES
Supports Action Replay cheat and edit the code base.	YES	YES
Built-in energy-saving design.	YES	YES
User friendly skinnable interface. Touchscreen or button operation. Supports Skin DIY.	YES	YES
Supports the Hot-Key SOFT RESET.	YES	YES
Supports the WiFi game, DS Rumble Pak, DS Browser.	YES	YES
Supports Download play.	YES	YES
Supports 4-scale-lightness adjustment ( DS Lite only ).	YES	YES
Free SDHC high-speed reader	YES	NO (comes with SD reader)

As you can see, the only real difference between the DSTT and the R4DS is the SDHC support. This is a big difference as most places are starting to sell only SDHC microSD cards.

DSTT video review/tutorial:

 

Setting up your DSTT: