IME with buying new bitmain miners (with the exception of the E3) the price always drops dramatically. I bought into the A3s paid 2500 for first 980 for the second and now they are 520 (perhaps the fork threat is causing this) but the point is, buying in at the beginning and hoping ROI is fairly difficult to achieve for me so far. I am getting close to A3 ROI after 2 mos, but if I had to do it again, I'd prolly wait until batch 2.
In fairness to bitmain, they do compensate with extremely generous coupons, that I appreciate.
There is a theory floating around, make with it what you will, that Bitmain (with the coupons) is cleaning out 'old stock' mainly scrypt-pow miners and a new miner at
the rumored hash of 1.5gh and 400 watts will be announced for fall 2018 delivery (pre-orders in June after a majority of coupons expire)...thus they will do what they
did last time..hash the NEW equipment themselves (like they did on the delivery gap on L3+'s from Nov 2017 to March 2018) being the main source of difficulty increase...
The difficulty for LTC increased almost 100% ..with not many if any, pow-scrypt miners hitting the world from Jan 2018 to Mar 2018...and the difficulty for LTC DOUBLED...
https://bitcoinwisdom.com/litecoin/difficultyMany of us expect the same game to be played if these miners exist, the announcement of the new 1.5gh 400w scrypt-pow miners for the delivery 1st week of 0ct 2018,
and meanwhile, Bitmain mines the first units themselves in their own data halls and again drives up LTC difficulty (or other crypto difficulties) up 100%
rinse/wash/repeat
Bitmain: evil is what we do and we do it well! (tm bitmain)