I'm somewhat new to turning (6 months of turning pens), but I am/was in a similar predicament. My options were to buy a low speed grinder and sharpening jig, which would cost $150-$200, or I could get a Woodchuck Pen Pro. Up until maybe a month ago, I got by using a diamond coated sharpening stone and sharpening my gouge by hand. Then, the Yellow Dino Bone Tru-Stone came. I'd already turned Wild Horse Jasper and Turquoise Tru-stone blanks without any problems. However, that Yellow Dino blank ate up my gouge and I barely knocked the corners off of the blank! I then made the decision to buy the Woodchuck, and I'm glad I did! That thing cut that Yellow Dino Bone like butter, and it's still sharp! I'll still need to sharpen the gouge (which will probably take a while), but even if I bought the grinder and jig, I'd be back and forth between the lathe and grinder a lot when turning some of the harder Tru-stones without the Woodchuck.
My advice is this; if you turn mostly wood, the sharpening jig might be best. If you turn a fair amound of harder synthetic blanks, the Woodchuck is the way to go. Sure, I'll probably get a grinder and jig down the road, but being in my final stretch of college, I don't have much money to spend, so I went with the Woodchuck.