Becky's house was lovely - spotlessly clean, good amenities, and in a good location where we were never more than a 10 minute walk from the heart of Vallatta. If noise bothers you greatly, bring ear plugs - it's a bustling neighbourhood in the heart of Valletta and during the day (if you're saying in the apartment) you'll hear the occasional beeps of traffic or locals having conversations. We arrived late on a Tuesday night and awoke to a LOT of street noise on Wednesday morning - but this didn't continue through the rest of the week, so I think it was a delivery day for local shops.
Location-wise, you're pretty much set if you stay here - a 20 minute trip from the airport, 15 minute walk to the Sliema ferry, a 10 minute walk from St George's Square, and a 20 minute walk from the main bus depot in Valletta, which provides transport links to the rest of the island. I highly recommend staying at Becky's!