If you like the idea of warforged, but would prefer a more primitive feel to your construct PCs, you might do well to add Remarkable Races: Relluk to your library. In this supplement, Alluria presents the title race as a kind of tiki warforged, ancient constructs built from volcanic stone, gems, and metallic "circuitry." If you can picture a D&D galeb duhr with metallic tattoos, you've got something close to a relluk's physical appearance. Relluks have certain construct traits like warforged, a breath weapon like (but less powerful than) dragonborn, and a unique method of reinforcing their bodies to compensaste for their inability to wear standard armor.
If a DM includes the relluk as a PC race, I can imagine some players grousing about the relluks' armor emulation and the special abilities—Alluria should not have called them "powers," since they do not in fact constitute 4e powers!—that each type of emulation conveys. However, the special emulation properties make up for the relluk's inability to wear armor, especially magical armor.
I like the relluk monsters/NPCs, but since they come in at levels 5, 7, 13, and 27, they don't cluster in a single tier closely enough to build interesting all-relluk encounter groups. Nor does Alluria actually provide any suggested encounter groups or plot seeds involving relluk monsters/NPCs.
In my review of Alluria's Remarkable Races: Entobian, I pointed out some formatting oddities and editing oversights that marred my enjoyment of the product, though not of the entobian race itself. Sadly, Remarkable Races: Relluk exhibits the same weaknesses. Strange formatting inconsistencies beset the product; for example, the first line of the first paragraph under "Overview" (p 4) is indented 1/4", but the indentation increases to 1/2" in the other paragraphs in that section; then, under "Physical Qualities," the indentation grows still larger. Why didn't the design team indent the paragraphs consistently, and why didn't the editors notice and ask them to correct the problem? Later, Alluria can't seem to decide whether to use "prerequisite" (singular) or "prerequisites" (plural) when a character needs the relluk race and the breath of steam power to qualify for a feat, or whether to capitalize words after colons in the armor emulation section. I just don't "get" this kind of sloppiness. I can write off a single error as a typo, but multiple repeated errors of the same type imply carelessness and inattention to detail.
With their similarities to both warforged and dragonborn, relluks prove somewhat less original than some of Alluria's other Remarkable Races. The mechanics seem to work fine, and the race does have some innovative features, especially the armor emulation gems. I don't have any strong objections to the relluk, but I can't get very excited about them, either. When I read Remarkable Races: Entobian, I started thinking about ways to add entobians to my campaign. Not so with the relluks.