I flew Pobeda a few weeks ago TXL-VKO-OVB and found it absolutely fine, at 172 EUR o/w including one suitcase and XL seating I thought it was a very good deal. As a tall person, I am a bit partial to LCC's because of the possibility to book an extra legroom seat for a small surcharge. Important here is to know the system - cabin bag is size limited (smaller than other carriers), and there is no food/drinks available on board for sale - they only serve tap water. Flight attendants were super friendly on both flights, all was on time and the XL seating not bad (but no recline).
Vnukovo is a good airport, less crowded than DME or SVO (although lines at immigration were quite long). Good food options at VKO as well.Overall, would not hesitate to fly them again.