Cool! I used to own those before I sold them once I started getting into the pricey valks. Another one you might want to check out is the Bandai Hi Metal series. The revoltechs are tiny, and the Hi Metal is a bit bitter, but more expensive than the Revoltech, obviously, but not as expensive as the 1/60s. It's in the 1/100 scale. I mean, you're still looking at about $70 per figure, but it's half the price of the new re-released 1/60's and everyone I've come across that has this one says it is the next best thing. Great articulation, almost perfect transformation (the landing gear doesn't retract and it gives two sets of wings. One for missiles, one without, and a heat shield. Basically you swap those parts out). It has some diecast in the feet and joints. Here's a video review of it. It looks fantastic:
http://www.youtube.com/watch?v=w3cxVCoshX4
Buy it here:
http://www.hlj.com/product/BAN958460
Next couple months they are releasing Roy's jet, but it's pricier due to having the fast packs.
http://www.hlj.com/product/BAN961438
Unfortunately, there is nothing in the quality and price range between the Revoltech and Hi Metal series. The Toynami 1/100s which would run you about $30 and are probably more solid than the Revoltechs, are pieces of shit.
The Revoltechs look nice but are finicky, so if you want a display model, Revoltechs are fine. But if you want a toy, you'll have to up your price to the Hi Metals.
Edit: Be careful about displaying your revoltech. I had mine in fighter mode on the stand, and because the stand is at the end of the nose, and the nose is a separate piece they glued on, instead of making the cockpit one complete piece, over time, you will see gravity start to weigh down the toy, and eventually the nose can split apart from the rest of the toy. I only caught this after a week and had to stop displaying it on the stand whenever in fighter or gerwalk mode. The nose of my valk was permenantly bent.
Luckily I had two at the time so I was okay with displaying the damaged one in battroid mode.