This company is a a part of Eurolines, which is variety of different coach companies around Europe that have joined together to offer a wide range of routes/services. I booked a journey with Slovaklines to get from Vienna to Bratislava and back.
The buses were both modern, clean and had good wifi available on board. I don’t recall any power points however, for such a short trip it’s not a necessity anyway.
A one way journey between Vienna and Bratislava is only around an hour and the ticket cost 7 euro (10 AUD). It’s was the cheapest public transport option I found to get to and from these cities.
I bought my ticket direct from a booth at the bus station in Vienna and there’s buses departing almost every hour to Bratislava (and vice versa) with a stop at the airport before you hit Slovakia.
Overall, my experience was without any troubles and I’d happily use them again! Slovaklines also have services to many other areas of Slovakia, in addition to Germany, Austria, the Czech Republic and more.