What was your decisive factor on getting the 410j opposed to the 410? Just like anything there are pros and cons to it all. From what Ive gathered, the DS410 outperforms the TS-419P in read / write using 9k MTU. I do plan on using jumbo frames and outweighs, to me, the convenience of hot-swap bays. I have been swayed and now leaning towards the 410. Ultimately it would seem that I would be at the max so upgrading, more storage capacity, would entail obtaining another device unless I bite the bullet and get a different one with more than 4 bays. My thing is that I do not like to be at the limit, due to the unknowns and what ifs. I want to be completely ecstatic and not just content with the final decision made. So that would bring up another question. Are they stackable?