Tankerbuilder-
I'm not sure if you're asking about the Revell Vasa? You mention Heller specifically, and I know they released a Vasa, though I think it was a re-box (?) from the Airfix kit. I can't testify to the quality of that kit, since I haven't built it, but I did put together a Revell 1:150 Vasa, and I really liked it. It's a new release, and the parts were all very crisp and had much detail. I didn't have any difficulty with the assembly...
I guess as with any other kit, it really depends on your experiences and preferences.
If you happen to have a Facebook account, I kept a lot of pictures on a public Facebook album while I built it, you can see them here:
www.facebook.com/.../set
I built it more or less *out of the box*, except that I ran my own thread shrouds, and made furled sails for it.
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Current Project: Imai/ERTL Spanish Galleon #2
Recently Finished: Revell 1/96 Cutty Sark
Next Up: ???