This huge box loaded with dials & knobs: if you get a mis-aligned, poorly treated one you'll swear (literally) that its the biggest piece of junk ever made. But if your RF-4900 is tuned up then you'll have a difficult time turning it off the first time using it. When properly aligned it pulls in signals almost magically with just a short piece of wire. It is fun to use. The massive size is a plus in my opinion, although the offical reviewer here apparently feels otherwise.
Its a mighty good MW (AM broadcast band) receiver just utilizing the rear-mounted loopstick. Shortwave, well what can I say? Its pulls them all in - easily. I do use this radio on sideband. A good time can be had there as well, provided that your antenna isn't too much and you manage to find yourself in an RF noise free setting. Yes, it does drift on sideband, but the instability can be mimimized to neglible by (a.) using battery or external DC power and, (b.) keep the dial lights off.
This isn't a serious Ham receiver. There will be noise and likely some drift. Don't be deadly serious all the time. Enjoy yourself. Buy one for $150 - $250 used. Keep your fingers crossed that its not a badly out of alignment unit.
Works OK for listening to strong international broadcast station, but so do most receivers.
The main drawbacks are its size and the lack of stability and selectivity. Furthermore, image rejection is poor on some bands.
The RF-4900 is a pretty good all rounder, considering its age. AM and FM reception are good, but for DX'ing you'd probably want something a little more advanced. For SSB listening the stability leaves some to be desired. You have to adjust constantly to keep the opposite station 'in focus'. Also, the frequency in the display is always a bit off, at least with my set.
Audio sounds very nice though. And I also like the looks of the beast. They just don't make proper table top receivers like this any more. I wouldn't consider parting with it, it's just too much fun to lister and operate.