These really are 5 1/2 x 2 3/4 x 1 3/8 "standard unit block" sized (I just measured). This measures the same as the Caroline Pratt standard (from 1900's!) which Beka and OldFashioned blocks uses (and probably several others as well). Which means you'll likely be compatible with those sets if you buy this M&D set. (not sure if M&D ever change their "standard", or if other brands do... so measure to be sure! also, there could be small tolerance differences so if you worry, just get them all from one place). I have read (at the OldFashioned Blocks website) that M&D blocks are made from RubberWood, which comes from old Latex plantations in Asia. The side of the M&D box says Thailand, but let's be certain: the quality is _nice_, just as I would hope for and expect for a nice set of hardwood blocks. I love these. And the price is right. So ... unless you want to buy "made in America" only, save your money, these blocks are nice, real hardwood, and the wood is left natural with no chemicals to finish them. There is no chemical smell like some other reviewers said. Maybe there is a faint smell of lumber... Nothing that wont fade after a while. There is _no_ paint or laquer on the blocks, completely natural. They feel slightly dusty, like sawdust, that's ok, makes sense. The ends of the blocks are completely smooth, not rough at all. No wood pores showing there, except within just a couple of the sanded corners in the whole set. Overall the woodgrain is very fine and doesn't seem to be susceptible to splintering either. Nice quality here. They feel heavy and dense (I haven't compared to Maple, but...), and feel hard/durable. The corners are sanded really nicely. They should be safe to use for kids. No sharp edges. The wood boxes are really nice as well. The box seems to be made of the same material as the blocks, and are a unit high to boot (so you can use the storage box as something to build upon!). The box is finished nicely, not _as_ rounded as the blocks, but not sharp either, certainly not sharp, nor splintery. maybe you'd like to put the box up so your kids dont fall and split their heads on it since it does sit up high and would be a nice and solid thing to crack your head on ... but really, if they fall and hit it, it's their own fault, accidents happen! (don't blame the toy... sheesh). The box came filled with blocks AND styrofoam, which is a great idea to leave a little room for dumping the blocks back in (as they take more volume when not perfectly arranged). I got 4 sets: 2 of the "standard unit blocks" sets, and 2 of the "architectural unit blocks" sets from M&D - 208 blocks total, for $196.60 total and $0 shipping. They make for quite a pile on the floor, and I love the building possibilities here. For me, I wouldn't want any less. For you... maybe the least quantity I would buy is 2 sets of the "standard unit blocks" if I was really on a budget. Certainly you can buy 1 and continue to add on... it's easy. Rubberwood: Density: 560-640 kg/mt3 Hard Maple/Sugar maple/Rock maple: Density: 720 kg/mt3 Melissa&Doug at 94 cents each block (Chinese hardwood, imported) compared to Beka Blocks at $2.09 each block (which are made of HardMaple, made in USA). I like the M&D better! Or my wallet does... To me, it is the worst to run out of blocks when building. So the M&D set lets me get 2x the blocks as the competition for the same price at a comparable quality. I seriously see no difference in wood quality. The M&D set is really nice, and lets me get more blocks! I'd like to include a bill of materials here, but I just am too lazy. But I will tell you (from my own memory) it comes with 2 of the 2x unit blocks (nice to know there are really long pieces, though more than 2 would have been nice); no quad unit blocks at all; around 4 of the 1 unit (rectangle) blocks; several 1/2 (square); several 1/4 unit blocks (or 1/2 unit length square 'dowel' however you want to look at it). 4 round dowel unit length columns. 2 arches, and 2 half circles that fit in the arches, and 1 circle cut into 4 quarterrounds (kind of a neat piece to use to finish off a model). 4 ramps (1 unit block cut long ways into a wedge). I may be forgetting some pieces, but that gives you an idea of the Bill Of Materials...