I also prefer the smart look of slimline and vertical blinds. I haven't had any maintenance problems with either to date. I use verticals on ceiling to floor windows and slimline on half-wall windows.
Blinds can also reflect heat away keeping rooms reasonably cool in Summer.
J. Parker also commented on this issue awhile back.
Just spent a touch over $3000 for curtains, after costing it all up curtains are only a little bit more expensive than blinds, and in my opinion look better. Also the perception to tenants are that blinds are a minimum requirement for a property whereas curtains are a luxury. Try and stay away from custom made curtains, thats what killed me, I had to get 3 curtains with a 300cm drop, 1 of them is $350. Getting a blind with a drop that size would have cost me more than the curtain.
Also I cannot stand the advertising most blind retailers like luxaflex use eg: 50% off, yet they never tell you what the original price is, either that or its always 50% off, they treat the public like they are complete fools, obviously some are because they keep using these tactics.
One final thing, Don't bother buying the $30 blinds that you see in Bunnings or Big W. I originally bought 2 and ended up using them for Drop sheets, as that was all they were good for.
I think my decision would be based on who would be renting my IP. If it was a prop aimed at dinks or single working class, I would go with blinds. If, however the IP was for a family, then curtains would definately be the go. Why. Just ask anyone with children just how long a set of blinds lasted in their house! They're just not child friendly. This is what I've been told by many a parent.
don't know about the $3000 figure mentioned above, I had verticals installed in 2 villa units (3 bedrooms each with big slider window for rear) at $1500 (it would have been around $750 each) with a big name company (Vista) & almost 2 years on I'm happy with their durability...
For something more glamorous I may even consider venetians (ie. timber) or curtains (for that extra feel of luxury)...
I purchased from a Factory outlet here in Sydney a full set of rubber backed, tab topped (x-Freedom Furniture) blinds for my whole house (6 large windows) for $125.
I must admit however that they were selling them out at 50% off the already discounted price. But there are other areas that you can get good cheap blinds from, so have a hunt around some factory outlets. The outlet I got mine from has closed down now, but was located in Alexandria.
I love the look of timber venetians and have them in the place I rent. I certainly wouldn't buy them for my IP's because they are a nightmare to clean. I'd buy timber look venetians so that cleaning could be as simple as hosing or dunking in the bath. You can't do that with wood!