Hello there. I'll do my best to give you an honest review. I'm not a huge fan of long drawn out reviews, so I'll try and keep this short, sweet and to the point. If you have any questions, comments or concerns I'll do my best to respond to those too.
I'll break down my review by sections in which I find important. This is only my opinion, I'm no one special so please don't take offence (it's not intended) or take my opinion as any kind of expert opinion.
The very first impression I have:When I first open the forum, I see a very simple but nice design. I am a fan of a forum that can look nice but not be too much on the eyes or brain. Many forums today over clutter the top of the forum with too much design, which gets hard to look at. Others add too much text information which overwhelms me and I often leave the forum.
Banner area/ menu:I really love how the background in visible through the banner, nice touch. The actual forum name might be a little too simple for me, but a simple design or effect might be the trick for me. I find the smaller, simple text gets lost in the transparency and is overwhelmed by the background. The text is small also in relation to the menu.
I like the menu, simple, visible and to the point. The mouseover effect is nice too. Huge Fan. Good use of the menu to add a rules link.
Header area(Between banner and boards):I find it hard to put a message area in the header that looks good, yours does. I see you have the message area and using forum news. I find it redundant and makes it look cluttered. I'd remove the news bar.
The wrapping you have around the content looks great. It's simple, which goes with the forum, small but adds a light effect to the forum that I like.
Boards:You have a decent amount of boards, which is okay since I find too many overbearing. I see a lot of sub-boards, which can be hard to navigate. Im not a fan of these unless the forum has the threads/ content to articulate it.
Misc/extra features:You've kept the generic Proboards layout here, and I like it. Keep it simple sweet. I really love how you've even kept the default images and made it work. I find that hard to do.
Overall:Like I think I've hammered in this post, I love the simple look. The forum is easy to view and navigate new users and the experienced Proboards users. I find the forum "kind of large" for the small header and banner area, though I can see how some users may like that. I'd keep the content specific or easy to view while the forum is small. Larger forums have really deep content because they have established users and roll out content to appease them. Pushing out custom content and specific content to a certain audience can definitely be your niche and the reason your forum flourishes.
I hope this helps at all. I enjoyed viewing your forum and wish you the best in the future and hope your forum thrives.