Tough question. I'd give Avodart a cautious thumbs up for tackling frontal thinning: my hairline (first half inch in) has v. slightly worsened since I made the switch you're currently contemplating, but this is off-set by a marked improvement to the area immediately behind the hairline (the next 2 to 3 inches in). So from the purely non-technical point of: 'When I catch a glimpse of my reflection in a shop window on a sunny day, how far back along my head can I see light bouncing off my scalp', I'd say it's been a positive move.
Now it took me a while to get to even that point: I had a fairly hefty shed between months 6 and 8, and it took a good year after then for the front to recover to its pre-shed levels. Then I had a few months of thickening in the 'behind the hairline' area mentioned above, followed by 2.5 years (and counting) of stability - except for the hairline whose (very) slow descent resumed around the 4-year mark.
Oh yes, if you do choose to make the switch: 0.5 mg (i.e. one capsule) Avodart per day; and I wouldn't bother combining it with finasteride.
Slarti
p.s. Of course you may wish to try another approach before Avodart: stronger minoxidil, Prox-N, a topical anti-androgen....