Short term, as a borrower, low rates are fantastic.
But really, long term, they're the sign of a sick economy. The rate of return of investment across an economy is the interest rate. Think of it like a balance sheet - if the economy is able to expense liabilities at a really low rate, then assets are also expensed at a really low rate.
Stable interest rates are great (across an economy, not individual rates - plus this gets really hard to measure where a banking system isn't the main source of capital, but I digress no more) are great. It allows planning.
Low (real) rates can seem great, but over the long term in a North American/European banking-funding centric economy (i.e. measurable), it indicates low increases on return of capital. And because of the low rates, an economy that is troubled in generating growth. My liability is your asset. If my liability is returning 0.5% real per year, as (real) growth, we're sitting stagnant.
As pointed out by someone else, a low rate also means revenue generating assets have a much higher price. That's because they're returning revenue, not growth.
Low real interest rates are really, really, bad.