Uhm. The doses of 25B are in the submilligram to 2 mg range. So there's a big difference there as far as potency.
I haven't taken 25B by itself, I only took it once and in combination with other things, but NBOMes in general do not really feel much like their vanilla PEA counterparts. I mean, NBOMes are certainly closer to PEAs than tryptamines, but the method of action, position of the molecule relative to the receptor when bound, electrostatic shape and steric bulk, even the result when binding does occur (PEAs are partial agonists, NBOMes are full agonists), are totally different.
I find NBOMes to be pretty boring on their own, really I get no mindfuck at all, no body buzz, just sub-par visuals. And I take high doses too, 2 mg minimum usually. So I only really use them in combination with other things, because I find that when they are combined with a proper psychedelic that does give me mindfuck and a body buzz, the result is more than the sum of its parts.
But some people have felt that they have achieved ego loss on NBOMes, and that they have achieved serious revelations on these drugs, so YMMV. I have hypothesized previously that any of 255 known SNPs – single nucleotide polymorphisms – that occur in the genes that encode the proteins for the 5-HT2a receptor, may cause people to react to full agonists with preposterously high binding affinities like the NBOMes differently. You see, SNPs are changes in the genetic code where a single nucleotide is changed (like an A or a C or a T instead of a G) that are generally harmless. SNPs are what those mail in DNA ancestry tests actually analyze, they don't sequence the whole genome, they just compare locations where common SNPs are known to potentially exist, which they can then correlate with racial or ethnic ancestry.
So an SNP is a change in a single nucleotide, as I said. This will make the amino acid coded by that nucleotide (it takes three nucleotides to determine what amino acid should be attached to the growing protein in to ribosome, and changing one of those three nucleotides can change the identity of the amino acid that is being coded for. The end result of this is that you end up with locations where there is a single amino acid that is 'not correct' in the structure of a protein, like a G protein-coupled receptor such as the 5-HT2a receptor (which has 255 known SNPs that may or may not occur in a given person). Luckily these incorrect amino acids don't usually do a ton of damage to the function of the protein, but it will change the shape of the folded up protein to one extent or another for each SNP that was there in the relevant piece of the genetic code.
These conformational changes in the proteins that make up the receptor could very well cause the people who's receptors harbor incorrect amino acids as a result of SNPs to react differently to the powerful agonism and high affinity of chemicals like the NBOMes. This would explain why the doses that people recommend vary so much (I've seen people say they'd take no more than 500 micrograms and people say they'd take four, five mg), and also why some people get profound effects while others such as myself get boring subpar visuals and not much else.
Anyway, I digress, this is all off topic here. But anyway don't expect a lot of parallels between them and for gods sake don't EVER try taking 2C-B level doses of 25B! That would be really bad, possibly fatal. I'd say start with a milligram if you're confident in your ability to handle psychedelic states.