I have them all in the mix and I find them absolutely compatible. The styles/proportions are close to each other and I can even interchange heads - the only problem are sometimes the old 25mm because of the smallish heads, but the proportions are similar and the weapons too. Copplestone has a distinctive style (which he hasn't treated us with more recently, sadly) of clean design and very consistent proportions throughout, but a limited range of postures, unfortunately, so needs enrichment by other ranges.