We were about to buy one a few weeks ago. It was in the shopping cart and everything.
Then it occurred to me.... you can only dig as deep as the shovel! Once the FEL hits the ground, the shovel can't go any further.
So we started looking at FEL forks for the fork mount version. That was going to cost $1K after everything was said and done.
Then I was going to build a stump bucket but the cost was within $50 of a Markham Grubber Bucket. So thats what we got. And after using it I'm positive it was the right purchase. And, I think, better than the fork mount shovel.
EDIT: Just noticed you have a 2305. Your tractor will not handle a Grubber Bucket well I don't think. I don't have any direct experience but I think my tractor is the bare minimum for it to be effective. It needs weight and lots of loader breakout force. With that in mind, if I were in your shoes, I'd be looking at the fork mount shovel.